[Exist-open] RESOURCE_ACCESS_FAILED during backup

[Alberto S. <has...@gm...>]

Hello

Triggering a full backup, I am getting this error:

...
  DOCUMENT: 108000 of 111595
  DOCUMENT: 109000 of 111595
  DOCUMENT: 110000 of 111595
  DOCUMENT: 111000 of 111595
  DOCUMENT: 111595 of 111595
----------------------------------------------
RESOURCE_ACCESS_FAILED:
Failed to access document data
Document ID: 170957

What can I do to:
 - understand what is the problematic document
 - try to understand if I had data lost
 - fix it :-)

Thank you in advance.

-- 
Alberto Simões