Thank you for logs!
According to log it has failed to create AeXNSClient service, during upgrade of Symantec Management Agent
*WARN AeXUtility: CreateService('AeXNSClient'): Failed to create service because the service is marked for deletion, waiting for it to be released, remaining retries 1440
Question:
1. Does this problem occur only on Windows 8.1 Enterprise x64 clients or on another OS as well?
2. Currently there is no AeXNSClient service is running on those problematic clients?
Attempt to solve a problem:
1. You can try to re-install Symantec Management Agent by push from SMP Console for these problematic clients
2. Or manually perform installation of SMA 7.5 SP1 on problematic client, via execution of AeXNSC.exe
Package is located on NS Server. You can download it on client PC from this location.
- \\<Your NS Server address>\NSCap\bin\Win32\X86\NS Client Package\
Thanks,
IP.