Acronis Backup 12.5 Known Solutions

Your Acronis Backup 12.5 quick troubleshooting kit. Below are the most recently published and the most popular articles. The solution you are looking for is most probably right here.

Most recent articles

Installation fails with the error "MainEngineThread is returning 1632"

You install the backup agent in a Windows operating system. Installation fails with these messages in MSI log (C:\ProgramData\Acronis\InstallationLogs\BackupClient.msi.log):

MSI (s) (6C:34) [17:13:02:292]: Note: 1: 1336 2: 3 3: C:\Windows\Installer\
MSI (s) (6C:34) [17:13:02:292]: MainEngineThread is returning 1632

Backup to a network share or a removable drive fails with "The end of the file has been reached"

You are saving backups to a removable drive attached to the protected machine or to a network share that resides on a removable device.

Backup fails with this error:

Error code: 2
Module: 4
LineInfo: 0xC1C09B38BAFA76A0
Fields: {"$line":"484","$file":"e:\\627\\core\\file\\windows\\win32_dir.cpp","$module":"isk_bundle_vsa64_15300","$func":"win32_dir::letter_iterator::Find"}
Message: The end of the file has been reached.

New tape is used for backup even when free space is available on the previous tape


New tape is used to continue backup when there is free space on previous tape.


Backup archive uses more tapes than required by its size: e.g. 14GB backup archive requires 17 tapes of 1 GB size. 

'Backup is missing' alert from a backup plan applied to a Hyper-V replica VM


You have a backup plan applied to a Hyper-V replica VM, where the backup agent is installed only on Hyper-V replica target host (no agent on source host).

After updating to Acronis Cyber Cloud v.8.0, you are getting the following alert from this plan triggered after some time:

Backup is missing: No successful backups for X days


  1. You create a plan to backup disks/partitions with the following parameters:
    • Backup format: Version 12 (.tibx)
    • Where to backup: internal or external disk
    • Backup scheme: full backup + differential backups
    • Cleanup: by number of backups (e.g. maximum number of backups= 3)
  2. You run the backup task several times;
Backup fails with "Windows error: (0x800705B4) This operation returned because the timeout period expired"


Activity fails with one of the following errors:

Windows error: (0x800705B4) This operation returned because the timeout period expired


Operating system error: This operation returned because the timeout period expired

Вackup fails with 'Common I/O error'

A Linux machine backup fails with this error message:

Message: Failed to create volume snapshot.
Error code: 5832705
Fields: {"$module":"disk_bundle_lxa64_15300","device":"/dev/md1"}
Message: Common I/O error.

You see these errors in /var/log/messages/
Jan  6 23:22:11 kernel: heartbeat_timer_func(swapper/0,0): Deadlock, cnt=6, state=4. Unfreezing...
Jan  6 23:22:11 kernel: find_deadlocked(snapapid,7404): dev=900001 state=1024
Jan  6 23:22:12 kernel: do_resolver(snapapid,7404): Real cleanup started... s=ffff9b7209fbc000(900001)
Jan  6 23:22:12 kernel: find_deadlocked(snapapid,7404): dev=900001 state=256
Jan  6 23:22:12 kernel: find_deadlocked(snapapid,7404): dev=900002 state=2

Logs in %ALLUSERSPROFILE%\Acronis\BackupAndRecovery\MMS\ consume a lot of drive space

After updating Acronis Agent to build 12.5.14800 or higher, logs in %ALLUSERSPROFILE%\Acronis\BackupAndRecovery\MMS\ consume a lot of drive space.

Installation on ARM-powered PC fails with "This app can't run on your PC"


Installation of Acronis Agent for Windows on a machine with ARM CPU architecture fails with:

This app can't run on your PC.


Acronis Backup 11.7, 12 and 12.5 and Acronis Cyber Cloud services (including Acronis Backup Cloud) do not support ARM and ARM64 CPU architecture.

These Acronis products cannot be installed on ARM-based machines.

Update permissions for Acronis Agent for Linux files to prevent unprivileged users accessing the files

We have recently identified a security issue within Acronis Agent for Linux installations that may potentially allow unprivileged users to access Agent logs and backup data.

We have identified that these files and directories have excessive read permissions (allowing users who are not functioning as backup operators read the files) and recommend to deny read permissions to all users other than 'acronis' group members to these files:



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Operation fails with "data is corrupted: CRC mismatch or internal data structures mismatch"


1.  Operation with a backup archive (backup, replication, validation, etc.) fails with the following message:

Data is corrupted: CRC mismatch or internal data structures mismatch

Backup fails with "VSS writer 'System Writer' with class ID 'E8132975-6F93-4464-A53E-1050253AE220' has timed out" error"

Backup fails with:

The backup has failed because 'VSS Writer' has timed out during snapshot creation



Windows error: (0x800423F2) VSS writer 'System Writer' with class ID 'E8132975-6F93-4464-A53E-1050253AE220' has timed out. This may be caused by too intensive I/O on the machine at the backup start time. Try to re-schedule the backup to some different time. To troubleshoot VSS issues, download and run Acronis VSS Doctor available at

Incomplete backups occupy space; how to delete

You start a backup plan for the first time. After the first backup has not completed (for any reason), you want to delete this incomplete archive, but cannot find it under Backups. Or you notice, that space used in Acronis Cloud is larger than your backups occupy.

"Failed to Connect to the Process" error

You may get the error as a result of exceeded timeout for disk system initialization. Disk system initialization is executed during backup. To fix it, add a value StartTimeout in Windows registry.

"The activity has failed due to a restart of the service" error

An operation in Acronis Backup 12.5 or Acronis Backup Cloud fails with "The activity has failed due to a restart of the service." or "The activity has failed due to an unexpected machine reboot or the backup process was terminated."

Machine is offline in Backup Management Console

After successful installation, the machine is offline in the Backup management console.

Backup finishes with warning "Creating a crash-consistent snapshot of virtual machine because the creation of its application-consistent snapshot has failed"

Backup of virtual machines finishes with warnings:

Creating a crash-consistent snapshot of virtual machine 'XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX' because the creation of its application-consistent snapshot has failed. Failed to create the virtual machine snapshot.

Manual registration fails with "Couldn't connect to host at localhost:43234" on Linux

You faced an issue with the registration of the Agent during the automatic installation and try to use the instruction from the article 55244:Acronis Backup Cloud: Registering Backup Client Manually

The RegisterAgent tool gives you an error:

| error 0x2260007: couldn't connect to host at localhost:43234
| line: 0xcbd08862963188d1
| file: e:/271/enterprise/common/http/curl_transport.cpp:284
| function: PerformRequest
| $module: register_agent_lxa64_10790

OR in Linux

The registration failed due to a problem on the Management Server. Either the backup service on this machine could not access the Management Server or the server returned an error response. Please make sure that the Management Server is accessible through the network and try again.

Backup to Acronis Cloud Storage fails with "Network disconnected by timeout"


Backup to Acronis Cloud fails with message:

Network disconnected by timeout

"VSS writer 'SqlServerWriter' with class ID 'A65FAA63-5EA8-4EBC-9DBD-A0C4DB26912A' has failed to process the snapshot"


Backup fails with the following message: