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Outlook Sync failed during PST backup
Updated over a week ago

Problem description

If the profile has Email option selected to backup as ‘Optimized with efficiency’. Backup fails at outlooks Sync stage. Email using Optimized for Performance gets backed up successfully.


inSyncUSyncer process is crashing as it starts backing up outlook.

Perform below steps to confirm :

  1. Stop Druva inSync Client Service.

  2. Start Druva inSync Client Service.

  3. Monitor processes in the task manager.

  4. Start the backup

After flat file data is backed up as it starts synchronizing outlook inSyncUSyncer will exit.


[2021-12-15 12:35:47,157] [INFO] Synchronizing Outlook Advanced
[2021-12-15 12:36:02,529] [ERROR] Error <class 'socket.error'>:[Errno 10054] An existing connection was forcibly closed by the remote host. Traceback -Traceback (most recent call last):
File "inSyncLib\inSyncRPCBase.pyc", line 505, in __recv
error: [Errno 10054] An existing connection was forcibly closed by the remote host
[2021-12-15 12:36:02,532] [WARNING] Outlook Sync failed: can't connect to USyncer.Network not reachable. (#100000022)
Log Name: Application
Source: Application Error
Date: 12/15/2021 2:42:14 PM
Event ID: 1000
Task Category: (100)
Level: Error
Keywords: Classic
User: N/A
Computer: XXXXX
Faulting application name: inSyncUSyncer.exe, version:, time stamp: 0x5f046ea7
Faulting module name: KERNELBASE.dll, version: 10.0.19041.1387, time stamp: 0x0b9a844a
Exception code: 0x80040813
Fault offset: 0x000000000010b302
Faulting process id: 0x1de8
Faulting application start time: 0x01d7f19329cc2b40
Faulting application path: C:\Program Files (x86)\Druva\inSync\amd64\inSyncUSyncer.exe
Faulting module path: C:\Windows\System32\KERNELBASE.dll
Report Id: 8c2bb8ec-3fb7-453a-a9fa-f7bdf8d3ff66
Faulting package full name:
Faulting package-relative application ID:
Log Name: Application
Source: Outlook
Date: 12/15/2021 2:42:14 PM
Event ID: 2000
Task Category: None
Level: Error
Keywords: Classic
User: N/A
Computer: XXXXXX
Database corruption was detected and the process was terminated.
Process: "<unknown_process>" (1de8.3b4)
Version: 16.0.10380.20037
File: "D:\Mail\My Outlook Data File.pst"
Last: "C:\Program Files (x86)\Druva\inSync\amd64\inSyncUSyncer.exe"
Database Version: 23 (2)
Context: 10037001
BCRead(@38CD629C0): Expected (bid=62BF920,cb=8176,dwCRC=A26A3244,wSig=5A1D), but read (bid=62BF920,cb=8176,dwCRC=4693ABAC,wSig=5A1D)

Repairing the PST file does not help.


Try repairing the PST file and then run the backup. If it still fails, Export all emails to a new PST file. Remove old problematic PST and attach new exported PST.


Backup should be successful for the new exported PST file.

Monitor task manager for inSyncUSyncer process, it does not crash.

See also

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