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The following error may appear in the application log when you mount a mailbox store after you run an offline defragmentation (such as eseutil /d):
Event Type: Error Event Source: MSExchangeIS Event Category: General Event ID: 9519 Computer: SERVER Description: Error 0xfffffde4 starting database "First Storage Group\Mailbox Store (SERVER)" on the Microsoft Exchange Information Store.
Running eseutil or isinteg to repair or verify the database also returns error -540 (0xfffffde4 in hexadecimal).
This behavior can occur when the defragmentation process is interrupted while copying the temporary .stm and .edb files over the original files.
To resolve this behavior, find the temporary files (TEMP####.stm and TEMP####.edb) and copy them back to their original location and original name. Be sure that the dates on the temporary files match the date that you ran the defragmentation operation. In addition, back up all files to a safe location before overwriting or deleting these files.
You can view the database signatures and creation dates by running the following two commands:
eseutil /mh streaming file path and filename eseutil /mh edb file path and filename
These values must match in order to avoid the error described in the "Symptoms" section.