Moved to Business and end point security area for a better chance of a solution
Would help to have some clarity to be able to offer some assistance...
What are OS are your client machines ? Windows 7 ? Windows 10 ?
If Windows 10, what update(s) are you installing ? is it the Fall Creators / 1709 update ?
In case of 1709, the disappearance may be due to the currently available version of Endpoint Security, 10.5.2, is not supported on that version. 10.5.3 is available RTS (ie contact Tech Support), and should be available for download via your Grant Number within the next couple of weeks.
If they aren't Windows 10, or if it is Windows 10, but normal updates and not the Fall Creators update, you may be better off logging a call with Tech Support.
Thanks a lot for the help, we do not know if this will solve the issue finally, but today McAfee released a new patch ENS 10.5.3 RTW, which should solve this problem
Thank you in advance!