Several times a week, the Viewer crashes with a run time error. There is a windows that pops up with the error code, but it goes away too fast for me to write the info down. But here are the two entries entered into Windows Event Viewer:
The issue can be occurring if some Viewer file were somehow damaged/corrupted. Could you please try fully uninstalling Viewer as described here and then re-install it from scratch? Before uninstalling Viewer please make sure to backup your address book, so that later you can restore it from the backup file. You will also need to register Viewer with your license key once again. In addition, please make sure that you've added Viewer installation folder to the exception list of any antivirus software that is installed on the machine (even if it's Windows Defender).