Symptoms

• After agent update, Continuous Data Protection (CDP) starts failing with "Driver not initialized"
• Recently, a Windows update has been installed on the same machine
• In the installation logs from the last Acronis update, you can see that the file_monitor driver has been deleted:
  
  Example of error message:

  DIFXAPP: ERROR: Unable to revert to a previous driver store for service 'file_monitor'.
  DIFXAPP: ERROR: Will attempt to uninstall the driver.
  DIFXAPP: ERROR: service 'file_monitor' failed to stop with error 0x426
  DIFXAPP: INFO: service 'file_monitor' was deleted.

  Also, there is an error that the same driver couldn't be found:

  1: [07:01:18:025]: (file_monitor) StartServicesAfterOldProductUninstall: Error 0x2be0006: Failed to start service 'file_monitor'.
  | line: 0x474cd3234f674b98
  | file: d:\512\inst_supp\service_supp\impl\windows_service.cpp:410
  | function: ServiceSupp::WindowsService::StartAsFilterDriver
  | $module: custom_actions_msp_vsa64_s_31037
  |
  | error 0xfff0: The system cannot find the file specified
  | line: 0xbd28fdbd64edb902
  | file: d:\512\core\common\error.cpp:324
  | function: Common::Error::AddHResult
  | code: 0x80070002
  | $module: custom_actions_msp_vsa64_s_31037 

   

Cause

During Windows update, the directory C:\Windows\system32\DRVSTORE has been changed to C:\WINDOWS\system32\DRVSTORE.

The driver locator is case-sensitive, thus agent is unable to find and start the existing driver.

Solution

To resolve the issue, change the %windir% environment variable from "C:\WINDOWS" to "C:\Windows"

More information about environment variables can be found in this Microsoft article

More information

If the suggested solution didn't resolve the issue, collect system information from the affected machine, and contact Acronis Support.