How to Reseed a Failed Mailbox Database Copy in Exchange Server 2010

When a mailbox database copy has failed in an Exchange Server 2010 Database Availability Group (DAG) it may be necessary to reseed the mailbox server with the failed database copy.

Exchange 2010 DAG with a Failed Database Copy
Exchange 2010 DAG with a Failed Database Copy

To reseed the database copy launch the Exchange Management Shell on the server that is in a failed state.

First we need to suspend replication for the mailbox database copy on this server.  Use the following command, specifying the mailbox database in the format “<mailbox database name>\<server name>”.

[PS] C:\>Suspend-MailboxDatabaseCopy -Identity "Mailbox Database 01\EX2"

Are you sure you want to perform this action?
Suspending mailbox database copy "Mailbox Database 01" on server "EX2".
[Y] Yes  [A] Yes to All  [N] No  [L] No to All  [?] Help (default is "Y"): y

The mailbox database copy status will now change from “Failed” to “Failed and Suspended”.

Exchange 2010 Mailbox Database in Failed and Suspended State
Exchange 2010 Mailbox Database in Failed and Suspended State

Next we reseed the database with a new copy by issuing the following command.

[PS] C:\>Update-MailboxDatabaseCopy -Identity "Mailbox Database 01\EX2" -DeleteExistingFiles

The duration of the seeding process will depend on the size of the database and the speed of the network. When the update has completed it will automatically resume replication for the database copy. If you want to prevent automatic resume of replication use this command instead.

[PS] C:\>Update-MailboxDatabaseCopy -Identity "Mailbox Database 01\EX2" -DeleteExistingFiles -ManualResume


  1. ZEFel says


    can u tell me how to bring back PAM role of my 4-node cluster – after some problem with network i have operational cluster but cmdlet Get-DatabaseAvailabilityGroup showing empty PAM and OS


    • says

      Hi ZEFel,

      To see the PAM and Operational Servers fields populated you need to include the -status parameter with Get-DatabaseAvailabilityGroup


      Get-DatabaseAvailabilityGroup -Status | fl

  2. Dave Purscell says

    Any way to limit bandwidth consumption during the reseed? Last time I did this I took down the VPN for several days. I really don’t care how long it takes to reseed if it can do so in the background.

  3. Dave Purscell says

    Is there a way to pause the reseed process, so that we can continue it later during off hours.

    Based on progress measurements, it appears the reseed will take another 32 hours to complete. We are performing it on the weekend with minimal staff, but we are consuming 100% of the VPN bandwidth.

  4. Hein Traag says

    Just wanted to pop in and say THANK YOU! We recently moved to a DAG environment and after a copy action two databases failed. Was able to get them going again with this how-to.

    Thanks again!

  5. David Fletcher says

    Thanks for your help. This is a great site that gives real solutions to problems that I am having.

    This a little weird. Why does the update database copy work when I do it from the EMS but from the EMC, it always goes back into failed state? Do you do everything from the EMS?

    • says

      I do most things from the shell. But the console gives you pretty much all the options you need for running a reseed, so I’m not sure why its failing for you. The event log should tell you more.

      • Dave Purscell says

        David is correct. I just did another reseed this weekend. When tried from the EMC it failed (after 6+ hours) due to a single missing log file. I ran the update copy again from the EMS and it went perfectly. Perhaps some parameter which is not being sent from the EMC.

  6. Jack Schweigel says

    We have to move all our Mbx Db on VMware from RDMs to VMDKs – 4 servers with 4 DB each = 16 DB. One DB active per server. Is there a variation of this process we could use? Something like – Add a new VMDK disk for each DB, incorporate into DAG, replicate, remove old (RDM) replicate DB and disks? Would need some specifics on that or a similar process.

  7. Richard Cunningham says

    Hi Paul, just investigating some weirdness which has happened in our exchange env, would the loss of FSW cause a failed & suspended status on our DBs?

    Basically, ETS had disappeared from the local admins group where the FSW was hosted, which caused the cluster to not be able to contact it… this coincided with our DBs going into a failed state…

    • says

      If quorum was lost then your databases will go offline. The loss of the FSW alone normally wouldn’t cause that, but I don’t know the full detail of your DAG.

      I do hear from people who have an undetected FSW issue, and find that their databases go offline when they’re doing patching/rebooting of the mailbox servers in the DAG.

  8. david sia says


    This proces did not work for me….

    even after the Reseeding I still get the “failed suspended”

    is there any harm in going into EMC and remove the “failed suspended” passive copy from the server..

    will this impact the Active copy of the DB



  9. Guido says

    Paul, just a dumb question, it is the same to run it from the active or passive node? Or should be on a specific one? If you could tell me why i will be appreciated! thanks!

  10. Alain says

    Thanks you for your post. I Still have one question. Is it ok to execute the command if I only have 30 Gb of free space for a 200Gb database?

    Do you know if the
    Update-MailboxDatabaseCopy -DeleteExistingFiles

    first delete the problematic database and after reconstruct them.

    Thanks you very much


  11. Andrew Roe says

    I tried this process and I get the following error:

    A source-side operation failed. Error There isn’t enough free disk space to perform this operation.. [Database: DB9, Server:]

    it seems like it is not deleting the existing files first? would there be an issue with removing some files manually then re-trying the command or should I blow away the whole copy and create a new copy from scratch (750GB database)

    • says

      Reseed includes the database file, content index files, and transaction logs. How much free space do you have on your DB and log drives for the source and destination servers?

  12. chander says

    Your Article is SuperB, got me out of a jam. Same issue, Failed Status.
    Fyi for anyone interested, while running the command to Re-Seed I rec. this error:

    Error: A database backup is already in progress, Please verify that no other seeding or incremental reseeding operations are started for this database, and then try the operation again by rerunning the Update-MailboxDabaseCopy cmdlet…

    There was a backup by commvault running at the time of this reseeding, re-ran this command during the day and Voila this Article worked wonders.

  13. mis says

    How to make the service replication running? the copy status in EX1 shows disconnected & resynchronizing.

    Failure mesage : A serve-side administrative operation has failed. The microsoft exchange replcation service may not be running on server EX01.___. com

    Specific RPC erro message : Error 0x6d9 (There are no more endpoints available from the endpoint mapper) From cli_GetCopyStatusEx2

  14. RMuhammd says

    I have a cross site DAG all is well in each site in terms of copies, test-replicationhealth. When i go to add copy in other site i am getting source-side communication errors. socket operation was attempted and unreachable on DAG nic IP for the source server.

    any help would be great! thanks

  15. SocalAdmin says

    Not sure exactly which process is triggering this, but every attempt to reseed a large database was getting interrupted hourly with a communications error. I’ve attempted from both active and passive copies of the database, as well as putting the seeding source into maintenance mode first. Nothing helped and this was the error:

    A source-side operation failed. Error An error occurred while performing the seed operation. Error: Communication was terminated by server ‘MB1’: Data could not be read because the communication channel was closed..

    Smaller .edb files that could copy in less than an hour succeeded every time, but the larger ones that took over an hour would fail 100% of the time. Resuming was not an option when this error happened.

    Based on the event logs, I was able to figure out the timing coincided with Microsoft Exchange VSS writer attempting to do an hourly backup. Event 4088 complains it cannot backup database because the copy is in the ‘SeedingSource’ state, followed by event 2045 VSS Witer failed with error 80070015 when checking volume dependencies.

    This only happened for the seeding database, all other databases backed up fine. However, as soon as this occurred the seeding was fatally interrupted and event 4104 triggered on the source server “Seeding from the passive copy for database to the passive copy on server X was cancelled … because the copy configuration changed on the seeding source’.

    It is definitely related to logs being replayed. However, this is supposed to be suspended based on the description of Event 4102 (“Passive copy of database on this server is starting a seed … Log replay ill be suspended for this copy and will be automatically resumed when seeding is complete.”) However, I have circular logging enabled, so this is my guess, as we run no third-party software in this environment but YMMV. I’m not in a position to turn that off at this time to confirm.

    The fix for us was to disable the Microsoft Software Shadow Copy Provider and Volume Shadow Copy services while seeding the logs. When the backup/replay routine was called, VSS would output errors 13 and 8193 to the event log (both related to being unable to start due to service disabled) instead of doing the above. We let two cycles of the log replay get skipped until the seeding completed (2h:30m in our environment) and then switched both services back to manual and let everything catch up naturally.

    This may not work for you in a snapshot-heavy/VSS-required installation or when available bandwidth will take you days to seed – so it would be interesting to know a more elegant way of handling this issue.

  16. bilal says

    Aoa dear,
    please tell me one question my exchange 2010 is properly configured all rules are set, all user are using in 2 database . first DB1 is 750 users and 2nd DB1 is 750 …. one DB1 are working good but the anpther DB are show error in webmail did you have any good solution.

  17. Gaurav K. Passi says

    Hi Paul,

    Once again, great and very helpful article!!!

    I’m running into a problem while seeding one of the databases to the passive server.

    We’ve 2 node multisite exchange 2010 dag. We’ve a dedicated 100 mbps connection between the sites.
    We’ve 4 mailbox dabases which are off different sizes. 2 small databases replicated properly and are online. 3rd database was of 75 gb in size and went into ‘Failed & Suspended’ mode after creating a copy. I was able to fix it using this very helpful article.

    My 4th database is of 195 gb and even after running this command, it’s still going into ‘Failed & Suspended’ mode. I’ve reseeded it twice but it doesn’t go into the ‘Healthy’ status even though the seeding completes without any issues.

    Can you think of any reason why this would happen. Can you please suggest a solution to fix this issue?

    Thanks in advance :)

    • Gaurav K. Passi says

      Sorry, forget to mention that the ‘Copy Queue Length’ is about 642,000 and it didn’t go down after the full backup of DAG.

      My ping response to the other site is 28ms.

      I’ve ran the command to test the replication and it don’t show any problems:

      [PS] C:\Windows\system32>Test-ReplicationHealth

      Server Check Result Error
      —— —– —— —–
      EXC01 ClusterService Passed
      EXC01 ReplayService Passed
      EXC01 ActiveManager Passed
      EXC01 TasksRpcListener Passed
      EXC01 TcpListener Passed
      EXC01 ServerLocatorService Passed
      EXC01 DagMembersUp Passed
      EXC01 ClusterNetwork Passed
      EXC01 QuorumGroup Passed
      EXC01 FileShareQuorum Passed

        • Gaurav K. Passi says

          Hi Paul!

          Thanks for getting back so quickly :)

          I went through the event logs and it shows that the seeding process completed properly:

          Information event id: 4135, MSExchangeRepl:
          Seeding operation from the active copy of database ‘New York’ to the passive copy of the database on server EXC02 is complete.

          Then there is this event log following earlier one:

          Error Event ID: 4113, MSExchangeRepl:
          Database redundancy health check failed.
          Database copy: New York
          Redundancy count: 1

          The details of the event logs says:

          Error: Passive copy ‘New York\EXC02’ is not in a good state. Status: FailedAndSuspended.

          ErrorMessage: The required log file 621253 for New York\EXC02 is missing on the active copy. If you removed the log file, please replace it. If the log file is lost, the database copy will need to be reseeded using Update-MailboxDatabaseCopy.

          I reseeded the database again and it still went into ‘Failed & Suspended’ mode.

          How can I have my database copy fully replicated and working without dismounting the original database and manually copying it over as a file to the passive server?

        • says

          I’ve seen a similar issue in the past, and the solution was to run a full backup of the database in question then try and reseed again. The full backup updates the log checkpoint and truncates the logs and should therefore resolve the missing log file issue.

        • Gaurav K. Passi says

          It worked this time. I just completed the reseeding of database copy and it’s healthy!!!

          Thanks alot for your help Paul :)

          One last thing. Are there any advanages or disadvantages in enabling ‘Circular Logging’ on the databases now that they’re fully replicated?

          The reason that I’m asking this is because we do ‘Full Exchange’ backups every night and if the circular logging is enabled then the changes are already been committed to the databases and it’s being replicated to the passive server also. Is it still worth to have the circular logging turned off.

  18. Ihsan says

    Hi there
    Please check the “Cluster Service” if it’s not started, this solution will not work.
    In my case, this was the problem why i couldn’t reseed the failed database copy.

  19. Anees Ur Rehman says

    Hi Paul,

    I am facing a problem with DAG

    I have 2 Mailbox servers in San Francisco and DAG is working fine on both servers.
    Now I have to implement DAG on a Server which is in New York. Everything is ok. Servers are accessible. I am able to ping the DAG from every server. There is vpn tunnel between sf and ny zone.

    But when I started the replication it gives the following error from ecp
    Passive Failed and Suspended
    Copy queue length: 8067
    Content index state: Suspended

    Then I started to reseed from EMS, I got following error

    The seeding operation failed. Error: An error occurred while performing the seed operation. Error: Communication was terminated by server ‘SanFrMailBoX1’: Data could not be read because the communication channel was closed. [Database: SFDataBase, Server:]
    + CategoryInfo : InvalidOperation: (:) [Update-MailboxDatabaseCopy], SeedInProgressException
    + FullyQualifiedErrorId : [Server=newyorkmbx,RequestId=cb11f9f1-4157-4e3a-a056-f35cf61db5ba,TimeStamp=2/7/2014 6:36:50 AM] 6079FA2A,Microsoft.Exchange.Management.SystemConfigurationTasks.UpdateDatabaseCopy
    + PSComputerName :

    Please suggest.

    Thanks in advance

    • Sumit says

      Hi Anees,

      Facing same error for DR copy across the WAN link. Please share if you have managed to identify the cause if the error while seeding.


  20. Philip Kitheka says

    Hi Paul,
    I am facing a problem with DAG in exchange 2010 sp1 environment.

    I have 2 Mailbox servers having a couple of mailbox databases (active/passive). i have been trying the reseeding operation on DTDB1 database without success. below is the error. the db size is 201.6GB. kindly assist.

    A source-side operation failed. Error An error occurred while performing the seed operation. Error: An error occurred while processing a request on server ‘EXCH-DRS-SVR02’. Error: An I/O error occurred while attempting to access file ‘I:\Program Files\ExchangeHome\Mailbox\DTDB1\DTDB1.edb’ on source server EXCH-DRS-SVR02. Error: SendSeedingDataInternal: PerformDatabaseRead fails with code 0xFFFFFC18. Expected 65536 bytes read 0.

    Copy Status: Failed and Suspended
    Content index state: failed
    Copy queue length (logs): 4718233
    Replay queue length (logs): 0

    Please suggest.

    Thanks in advance

  21. Trra says

    Hello Experts,

    My reseed has been running for days! 1 TB DB over wan link.. Can I run backup while reseed in progress?


    • says

      Nope, reseed and VSS backups can’t run at the same time.

      1TB database size is a risk if you’re having to reseed across a WAN. I would prefer multiple, smaller databases in that situation.

  22. Jay says

    Hi – Your solutions worked fine but after multiple attempts as for some reason it was failing because of Win Rm service going down. Thanks a lot for your blog. keep writing :)

    on side note, do you know is there any way i can replace existing FILE witness server with new server ?
    we have two Exchange server running DAG and one file witness server (server 2003) and file server is failing for past few months and i was thinking to replace with latest 2008R2 File server.

    Thanks again

    • says

      You can change the FSW any time using Set-DatabaseAvailabilityGroup. You just need to set up the permissions first (ie add Exchange Trusted Subsystem to local admins group on the new FSW) and also be aware that in Failover Cluster management tool the old UNC path will still appear in the name of the FSW resource.

  23. Adam Fowler says

    Great instructions. Although I didn’t use the -manualresume switch, it didn’t automatically resume replication. I manually resumed and it worked perfectly.

  24. Jesheem says

    Hey thanks for the tutorial.
    I am facing a situation wherein my Mailbox Database is in a healthy state. But the event viewer throws up the error “A source-side operation failed……”
    I did try the “Update-MailboxDatabaseCopy -Identity DB1\MBX1 -CatalogOnly” command. But it still throws up the same error.

    Should I go ahead with the method mentioned here?

  25. AKhil says

    Hi Paul,

    I have some query which is mention below.

    1) will on premises exchange will be finished from industry
    2 ) is Microsoft planning to introduce next version of exchange for on premises or they will only consider on online exchange.
    3) is Microsoft planning to flush on- primises

    I known these are stupid query but for being exchange person we should be aware before some disaster , so that we can start leaning new technology.

    As i know maximum customers are deploying hybrid not full cloud that indicates that no one is prepare for full cloud, but we are scare.

    Please reply my query

    • says

      As far as I am aware Microsoft has publicly stated that they plan to deliver another version of Exchange for on-premises customers. We can probably expect to see a preview of that later next year and perhaps it will ship in 2016.

      I would not wait before learning new technologies.

  26. AKhil says


    so can be Microsoft remove exchange on-premises in future .

    personally do you really thing that every customer will go for cloud or customer will demand for on-premises ?
    because as i aware every is going with hybrid not full cloud . what do you say?

    • says

      I can’t predict the future and I’m not going to just guess what Microsoft plans to do.

      Try to avoid guessing what “every customer” is going to do or is doing. There’s a lot of different customers around the world and they all have their own special needs and circumstances.

      I expect some percentage of customers will go full cloud, some will go hybrid, and some will always stay on-premises. Beyond that there is nothing I can predict.

  27. Alexander says

    Hi Paul,

    every time I move one of my copies,the copy status stuck at initializing and I cant reseed. I used your method but I get the following error:

    WARNING: The Microsoft Exchange Replication service has not responded to the suspend request yet. The service may not
    be running. Press CTRL+C to stop waiting for the service to respond. You can check to see if it is suspended by using
    the Get-MailboxDatabaseCopyStatus cmdlet in the Exchange Management Shell.

  28. Dennis Hartmann says

    Paul, I reseeded after the active copy got corrupted due to the logs filling up the logs HD. The DB failed over to the passive but the now the new active DB throws me this error: “The active copy of MBDB02 has a missing or corrupted log file (E06002526D1.log). To keep this copy healthy, replication will restart at generation 2434770. A full backup must be performed before an incremental backup is possible.” I’m currently performing a full backup but in the meantime, the CQL is rising steadily. Any idea what’s happening?

  29. Ed Kummel says

    Thanks for your continues support and information to the Exchange community. I rely heavily on the things you post.
    I have one question regarding reseeding the database.
    Recently, one of the drives in my JBOD DAS on one of my servers threw a predictive failure. The database never showed failed.
    The vendor replaced the drive and the new drive is now working fine.
    During all this, the mailbox databases affected by this JBOD DAS never showed “Failed”.
    Do we still need to reseed the database even though the database never failed in the first place?

    • says

      Was it a JBOD volume hosting the database copy? Ie, the only disk that had that database copy on it? If so, I’m surprised it isn’t failed. Maybe it was actually a RAID volume?

  30. Mark Adams says

    Hi Paul,

    I have a DAG active and passive, with a separate replication network (172.x.x.x). If I reseed a failed DB will the reseed using the replication network rather than the data (10.x.x.x) network? The replication network is on a separate switch with no access to the data network.


      • Mark Adams says

        Thanks Paul, one last question, I’m trying to reseed via the EMC by right clicking on the db, and selecting “Resume Database Copy” is starts then fails. The event log shows its missing a log file, but I’ve checked the log folder and the missing log is there, in the active log folder and the passive log folder?


      • Barton says

        Hello Paul,

        I will need to take down the passive copy of my two-member DAG very soon for at least a good number of hours. I remember when I did this the last time, the queue got so big all efforts to reseed the passive copy failed. If worse comes to worse, should I simply delete the passive copy in ECM, delete the EBD database and logs on the passive server and then make a new copy in ECM? Would that work?

        Also keep in mind as long as the replication between the two Exchange servers are being held up, I cannot run a full backup and flush the transaction logs. That can also be a problem. Is there a way to stop all replication just so that I can run the backup and flush transaction logs?

        • says

          Suspending replication on the DB copy will still cause the copy queue to build up.

          If you know it’s going to be down for a long time and that it will impact your disk capacity and/or backups, I suppose you could just remove that database copy and re-add it later. Understand the risks of this, you’re reducing your copies of that database by 1…

          Otherwise, if a database copy won’t resume or is otherwise failed you only need to reseed it using the steps shown in the article above. No need to manually delete files or remove/re-add the DB copy.

  31. DaveZ says

    Hi Paul, I have used this procedure many times in the past with great success. Thank you for that.

    This time I ran into an error:

    “A source-side operation failed. Error An error occurred while performing the seed operation. Error: The process cannot access the file ‘D:\
    Exchange\DB\DB11\DB11.edb’ because it is being used by another process…”

    Not sure what this means, or how to remedy it.

    Thank you in advance!

  32. TheK says

    Thx Paul for ExchangeServerPro articles. Saved my day many times, you rock dude. Thanks for sharing your knowledge.

  33. Chaitu says

    Hello Paul,

    Your articles are precise enough to easily understand! Appreciate the effort.

    We are going to have to rebuild one of the servers in a 2 Member DAG. I was planning on leveraging the RecoverServer switch for this with reference from the article

    However, I have a question, as per the article above, it is recommended by Microsoft to remove any Database Copies on the server that is going to be recovered (in my case rebuilt). I do that before OS recovery and once the server is up and running, when I add back the database copies on the rebuilt server, is it ok to leave the Database and Log Files (before recovery) in the directories as they are? Will the seeding from active copy happen with the delta only?


      • Chaitu says

        Hello Paul,

        Thanks for the quick reply, just curious to know what would be the implications if I leave them in the same drive? I have ran this in a lab, it seem to sync from where it left off, but small databases in the lab, no particular way to figure out if it copied over the delta or the whole database altogether.


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