Unable to change file permissions with file manager in Plesk: Cannot read properties of undefined (reading 'map')

Symptoms

• The following error show up in Plesk when trying to access Domains > example.com > Dashboard > Files or to change permissions there:

  CONFIG_TEXT: Error TypeCannot read properties of undefined (reading 'map')

  CONFIG_TEXT: Error TypeCannot read properties of undefined (reading 'state')

• Plesk backup finished with the following error

  PLESK_ERROR: Task failedUnable to copy file or directory: Access is denied. (Error code 5) at Unable to copy (C:\Inetpub\vhosts\example.com\path\to\file) to (C:\Inetpub\vhosts\example.com\different\path\to\file)
  at (zif_plesk_ex_copy line 1767)

Cause

Incorrect permissions in website's file prevent Plesk from reading its file attributes.

Resolution