After updating to 7.6 HF4 Task Server service does not install to site servers or does not update to 7.6.1625 on existing site servers.
Note this only applies to 7.6 HF4. If you have a prior version of 7.6 and .NET 4.6 installed in your environment see Tech232012
First ensure that the Symantec Management Agent is up to date (7.6.1625). If the agent has been updated and the filters on SMP have been updated then the problem may be caused by .net 4.6 being in the environment and the filters are not updated.
Note that .Net 4.6 is supported with 7.6 HF4
To check site servers for .Net 4.6 do one of the following:
1. Check the database by selecting the proper resource guid from the Inv_AeX_AC_NetFrameworkVersions table
2. Go to the machine and use regedit to browse to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full and compare the Release or Version key. See this Microsoft KB for more details.
If you have confirmed that .Net 4.6 is on the site servers then the Potential Task Servers and Computers without NET.Framework 4.5.1 installed filters need to be updated. You can update those filters by running the attach .sql against the Symantec CMDB database
This issue is expected to be addressed in the next hotfix 7.6 HF5