A few endpoints in the environment or site servers hang when rebooting on the last step of a patch reboot step.
ITMS 7.6 HF7
There may be various causes for these symptoms. The one that we identified was Microsoft's MRXSMB.sys library leaves connections UNC file download session open.
The workaround is use HTTP or HTTPS traffic rather than both IIS and UNC package downloads.
A fix for this is to install the post ITMS 7.6 hf7 rollups, by upgrading to ITMS 8.0, or by investigating Microsoft UNC library fixes specifically to new version of Mrxsmb.sys and Mrxsmb20.sys (some MSFT documentation can be found at https://support.microsoft.com/en-us/kb/3031085). The Symantec post hf7 rollup can be requested through support and referencing bug 3903815.