These instructions are in an external KB doc (# 315473), but for some reason the external link is not working currently (having that looked into). In the meantime, try these steps and see if the "job log" registry path got erased, changed, or corupted for some reason:
- Stop BE services using ServicesMgr.exe
Warning: Incorrect use of the Windows registry editor may prevent the operating system from functioning properly. Great care should be taken when making changes to a Windows registry. Registry modifications should only be carried-out by persons experienced in the use of the registry editor application. It is recommended that a complete backup of the registry and workstation be made prior to making any registry changes.
- Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\Backup Exec For Windows\Backup Exec\Engine\Misc
- Find the key "Job Log Path" and note the value (path)
- If the key is set to a non-existent directory, change it to the default directory (but be sure it exists first) <drive letter>:\Program Files\Symantec\Backup Exec\Data
- Start the BE services using ServicesMgr.exe
- Run a test backup and check for the Job Log tab in the Job History