NVP vProxy: FLR fails on Windows VM "The filename, directory name, or volume label syntax is incorrect"

NetWorker VMware Protection (NVP) vProxy File Level Restore (FLR) is performed on a Windows Virtual Machine (VM).
The FLR operation fails, reporting the generic error "Some objects or security properties could not be recovered"
The full recover log details the following error for some file paths: "The filename, directory name, or volume label syntax is incorrect."

152791:nsrvproxy_flr_recover: vProxy Log Begins ===============================================
159373:nsrvproxy_flr_recover: vProxy Log: 2020-03-05T21:11:58Z NOTICE: [89] Logging to '/opt/emc/vproxy/runtime/logs/vflrd/recover-xxxxxxxxxxxxxxxxxxxxxxxxx.log' on host xxxx'.
159373:nsrvproxy_flr_recover: vProxy Log: 2020-03-05T21:11:58Z NOTICE: [89] Release: '4.0.0-11_1', Build number: '1', Build date: '2019-09-06T12:54:06Z'
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159373:nsrvproxy_flr_recover: vProxy Log: 2020-03-05T15:11:59-06:00 ERROR:  [89] Discovery: Cannot get security data for 'C:\Program Files (x86)\EMC\vProxy FLR Agent\flr\mountpoints\FLRXXXXXXXXX\00-E$\SOME_LONG_PATH\FILE_NAME': The filename, directory name, or volume label syntax is incorrect.
159373:nsrvproxy_flr_recover: vProxy Log: 2020-03-05T15:11:59-06:00 WARN:   [89] Discovery: Cannot get attributes for 'C:\Program Files (x86)\EMC\vProxy FLR Agent\flr\mountpoints\FLRXXXXXXXXX\00-E$\SOME_LONG_PATH\FILE_NAME': Cannot get security data for 'C:\Program Files (x86)\EMC\vProxy FLR Agent\flr\mountpoints\FLRXXXXXXXXX\00-E$\SOME_LONG_PATH
159373:nsrvproxy_flr_recover: vProxy Log:  SOME_LONG_PATH\FILE_NAME': The filename, directory name, or volume label syntax is incorrect.
159373:nsrvproxy_flr_recover: vProxy Log: 2020-03-05T15:11:59-06:00 INFO:   [89] Recovery: XXXX - FILE_NAME
159373:nsrvproxy_flr_recover: vProxy Log: 2020-03-05T15:11:59-06:00 ERROR:  [89] Recovery: Cannot create handle for 'C:\Program Files (x86)\EMC\vProxy FLR Agent\flr\mountpoints\FLRXXXXXXXXX\00-E$\SOME_LONG_PATH\FILE_NAME': The system cannot find the path specified.
159373:nsrvproxy_flr_recover: vProxy Log: 2020-03-05T15:11:59-06:00 INFO:   [89] File copying completed.
159373:nsrvproxy_flr_recover: vProxy Log: 2020-03-05T15:11:59-06:00 ERROR:  [89] C:\Program Files (x86)\EMC\vProxy FLR Agent\bin\vflrcopy.exe: Some objects or security properties could not be recovered.
159373:nsrvproxy_flr_recover: vProxy Log: 2020-03-05T15:11:59-06:00 TRACE:  [89] C:\Program Files (x86)\EMC\vProxy FLR Agent\bin\vflrcopy.exe exiting with status code 0
152793:nsrvproxy_flr_recover: vProxy Log Ends =================================================
163541:nsrvproxy_flr_recover: FLR recovery failed: error code: 0, error message: Some objects or security properties could not be recovered.
162216:nsrvproxy_flr_recover: FLR recover job completed with errors.
164970:nsrvproxy_flr_recover: Requested termination of the FLR mount session 3098161.

The FLR logs can be found in the following locations:

• vProxy: /opt/emc/vproxy/runtime/logs/recycle/vflrd/DATE
• Windows VM: C:\Program Files (x86)\EMC\vProxy FLR Agent\logs\vflragentd\vflragentd-agent.log

Windows APIs (especially Win32) limit file paths to 260 characters (MAX_PATH). The file paths reporting this error exceed 260 characters. This limit includes drive letter, colon, backslashes, folder names, file name, and file extension.

Starting with Windows 10 version 1607, Server 2016, and later, you can enable long path support on the operating system.

This can be done using a Group Policy or registry change on the target Windows VM:

Go to Local Group Policy Editor → Computer Configuration → Administrative Templates → System → Filesystem. Enable "Enable Win32 long paths."

Or set the registry key:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem]
"LongPathsEnabled"=dword:00000001

Similar errors may appear if Windows Deduplication feature is enabled: NVP vProxy: Windows VM File Level Recovery Fails for Some Files With Message "Some objects, or security properties could not be recovered."