Acronis True Image 2018: Error when backing up OneDrive folder

Symptoms

Files and folders backup including OneDrive folder fails.

Possible error messages are:

Failed to enumerate directory 'C:/Users/myusername/OneDrive/'. It may be corrupted or does not exist. 

Failed to back up file or folder. C:/Users/myusername/OneDrive/' It may be blocked by another application

If you exclude OneDrive folder from backup source, backup completes successfully.

Cause

OneDrive can restrict access to files and Acronis True Image is unable to back them up.

Solution

To resolve the issue, do the following:

1. In OneDrive Settings disable the option Save space and download files as you use them
2. Wait until all files in OneDrive are syncronized to the computer. Note that synchronization may take considerable time if there are many files to process.
3. Create a new backup task and run the backup. You can also continue to use existing backup task but please be aware that recovery from old backup slices will not be possible.