This may be a possible bug. I had an image file set I was trying to manually Verify. However, when the Verify was started, Macrium Reflect got locked up. It was stuck at 0% and the image file name was "flashing" like in a previous bug I reported last year. However, this time, the only way to resolve the issue was to CTRL+ALT+DEL and close off Reflect. Cancel button doesn't show up until you press CTRL+ALT+DEL like in the previous bug. But, pressing Cancel does nothing to stop the operation.
Thinking it may be a problem with the image file name propagating the window like in the previous bug, I renamed the file set parts from Dell XPS 8930 Factory Default Windows Partition (Windows 10 1809)-00-00 to 00-00, etc. With the shorter file names, the Verify process starts.
This issue happens even in the root directory of a partition, so it's not a file name issue as regards to the name of the folder where it's stored. It's the file name itself that seems to be problematic.
The image file set in question was split at the 4 GB mark and split into 4 parts, if that is required specifics to recreate the issue.
EDIT 1: Discovered a pertinent piece of new information. What is happening is the Verify actually does apparently appear to be running, it just seemed to be stuck because of the sheer size of the data set I was first testing. I came across a 2nd image file with such a long file name, but it was really small. It's Verify actually did complete, but the window with the OK button saying it had completed did not appear until I pressed CTRL+ATL+DEL to bring up Task Manager. So, it does appear the Verifies are running, but you can't Cancel them because of this window flashing.
EDIT 2: Turns out the information in the above EDIT 1 is NOT accurate. The hard drive indicator light does not flash when this image file is being accessed. This indicates the Verify actually is NOT doing anything with the image file. For whatever reason, it worked on the smaller image file because of its smaller size, apparently.
EDIT 3: If necessary, for debugging purposes, I can put the small image file on my OneDrive account for downloading and testing like I did last year. It's small enough to download, it's password protected, and the partition backup contains no personal information.
EDIT 4: This issue sure seems related to the one I posted last year. Discovered I can get the Ok/Cancel/Yes/No windows to appear if I just press the ALT key, like before. No need to press CTRL+ALT+DEL. Just the ALT key is necessary.
EDIT 5: I went ahead and put the smaller image file on my OneDrive account on my own initiative: https://1drv.ms/u/s!AgRNx8Q17xvfi03cZlezGRPqc3MM
The image file name that causes the issue in this case is Dell XPS 8930 PC - SSD - Partition 2 - None - Unformatted Primary-00-00
EDIT 6: Here's the original post I made last year about this issue. https://forum.macrium.com/Topic24355.aspx
It seemed to have been addressed but maybe it's regressed in recent updates? Resizing the window as stated in the original thread works, at least it does in Win RE; haven't tried it in Windows.