As posted, your question/report lacks a lot of trhe minimum sufficient details that anyone would need to help. Like, what operating system, how much RAM, etc, etc.
However, hazarding a wild guess its a Windows 10 machine, have a look at the last part of the following -- about trying MARK in 'compatability' mode:
I finally had my hands on a computer where this particular bug occurs -- a Win 10 machine of recent vintage. I tried re-installing an older version of MARK, and the error persists (suggesting the problem isn't lkely due to a new feature in the MARK GUI -- of which there have been several), but, more likely, some recent tweak/chnge in Win 10, interacting with one or more programs/utilities/drivers on said machine (it isn't Win 10 generically, since it does run run on most Win 10 machines -- just not all of them). While figuring out exactly which element of the Win 10 environment is conflicting with MARK might be a fun exercise, it is far simpler to, as suggested, simply set MARK to run in compatability mode.
So, simply right-click the MARK icon, select the 'Compatability' tab, and have MARK run in either Win 7 or Win 8 compatability mode. Seems to do the trick.
Worth a try.