How to Fix Exchange Error Unable to Mount Database

 or ERROR: Microsoft.Exchange.Data.Storage.MailboxOfflineException

• First of all backup the edb, logs, and stm files




• Then make sure you have 110% Free Disk Space




• Now check your Database consistency – Dirty shutdown or Clear




• To check a consistency on database run:
  

  eseutil /mh "path of .edb"
  Like: eseutil /mh “c:\db\mailbox database.edb”

   

• See the database status, If it will be: Dirty Shutdown.




• First try Softrepair: by running
  

  eseutil /r

  
  
  You need to run this from database log folder and specify log chk file like;

  c:\dblog>eseutil /r E00
  Else, specify following:

  eseutil /r "prefix"<E00> /l <exchange log file location> /d <exchange database location>

  This looks like:

  Eseutil /r E00 /l c:\dblog /d c:\db

• Now check the Consistency again and If Softrepair doens’t work try hard repaire.Make sure the databases are dismounted.Before running the Hard Repair, It’s always recommended to make a copy of the .edb , .stm and pub.edb , pub.stm
  
  eseutil /p,Eseutil /p “mailbox database.edb”

  
  Eseutil /p "c:\program files\exchsrvr\mdbdata\priv1.edb"

• Defragment the database defragmentation of database:
  
  eseutil /d

  
  Eseutil /d “mailbox database.edb”

  How to defragment with the Eseutil utility (Eseutil.exe):

https://support.microsoft.com/en-us/help/192185/how-to-defragment-with-the-eseutil-utility-eseutil-exe

Before mounting database you must move/remove log file.

• Now check Database Integrity
  
  This we can skip it after softrecovery.To check the integer of database:

  
  isinteg -s "servername" -test alltests

  
if integer check fails, try:isinteg -s "servername" -fix -test –alltests

  Sometime we have do this multiple time till all errors have level 0 or the status has no changes.

  Description of the Isinteg utility:
  https://support.microsoft.com/en-us/help/182081/description-of-the-isinteg-utility