UPDATE: The post previous to mine mentioned adding files to the A/V and firewall exclusions list for another security software program, so initially, it was the one thing I didn't do that was suggested in this thread since I didn't think it applied to CA 2010. But then I found a similar post that advised performing the same process in CA 2010. Once I added those noted exclusions to my CA A/V (under My Computer/Threat Settings) and firewall (under My Computer/Program Access (adds only the EXE files)), it still didn't work until I took it one step further. To get to advanced program permissions, I had to hit the Edit button on the MBAM.EXE and MBAMGUI.EXE files under My Computer/Program Access. I then checked off the first four items and hit Apply. Not sure if I needed to check off all four of those items, but I wanted those settings in any case--you may want to test each one individually to see what works and what doesn't. It appears these advanced permissions are the crux of the matter--at least there were in my case. Also, I don't know why I had 4-5 instances of each EXE file in the list under Program Access, but I didn't remove them and performed the Edit on each instance. No reboot was required after performing these operations. Once completed, Malwarebytes updated successfully. After spending most of the evening trying to figure this out, I hope this helps someone else before they spend too many hours on this issue.