Avamar: Windows FS Plugin - Backup completing with exceptions with warning: avtar Warning <18834>...

Windows File System backup completes with exceptions.

• The backup log shows several warning messages similar to these:

  avtar Warning <18834>: Avtar has detected a circular Reparse Point (C:\ProgramData\Application Data\)
                          that points back to a parent directory (C:\ProgramData\). This may cause undesirable results, such as OpenFile Errors.
  
  avtar Warning <18834>: Avtar has detected a circular Reparse Point (C:\Users\Default\AppData\Local\Application Data\)
                          that points back to a parent directory (C:\Users\Default\AppData\Local\). This may cause undesirable results, such as OpenFile Errors.
  
  avtar Warning <18834>: Avtar has detected a circular Reparse Point (C:\Users\Administrator\AppData\Local\Application Data\)
                          that points back to a parent directory (C:\Users\Administrator\AppData\Local\). This may cause undesirable results, such as OpenFile Errors.
  
  avtar Warning <18834>: Avtar has detected a circular Reparse Point (C:\Users\<_user-id_>\AppData\Local\Application Data\)
                          that points back to a parent directory (C:\Users\<_user-id_>\AppData\Local\). This may cause undesirable results, such as OpenFile Errors.

• Enabling the log debugging we then see the following type of messages:

  [avtar]  GetReparsePointInfo() 'C:\Users\####v\AppData\Local\Microsoft\Windows\INetCache\Low\Content.IE5' does not have a resolveable target
  ..
  [avtar]  INTERNAL ERROR: <0001> assert error (inAbsTarget.is_absolute()), reparse_points.cpp line 81
  [avtar]  SessionProfile::sendstats kind: INTERNAL  mess1:
  <INTERNAL>assert error (inAbsTarget.is_absolute()), reparse_points.cpp line 81</INTERNAL>

• The same error can also be seen as "reparse_points.cpp line 84" and "reparse_points.cpp line 85" which is essentially the same error:

  [avtar] INTERNAL ERROR: <0001> assert error (inAbsTarget.is_absolute()), reparse_points.cpp line 84
  [avtar] INTERNAL ERROR: <0001> assert error (inAbsTarget.is_absolute()), reparse_points.cpp line 85

• When excluding using the dataset or command line in the affected folder, for example, "C:\ProgramData\Application Data\" the issue persists and the backup agent is still querying that path.

This issue happens on the Windows recursive or circular "Reparse Points" also known as "System directory junctions"

The internal assert error is associated to invalid targets that cannot be accessed and they cannot be backed up, this is an environmental issue.
They may be disconnected reparse points that are not needed anymore or there could have an issue with the reparsed point link. We recommend that the system administrator review and fix as needed.

To work around this issue, the Avamar developers have created a flag to work around this issue.

Option 1:

• To resolve the issue, request your system administrator to review the reparsed points that are affecting the backup and have them addressed before running a new backup.

Option 2:

• To work around the issue, use the flag "--x31=134217728" in avtar.cmd, which is in Avamar software version 19.4.X and later releases to disable circular reparse point check