The only workaround that seems to work is to keep Kutools DISABLED until I need to use a feature. Then I am able to activate it and do the task and disable it again before Excel gets too corrupted to stay open. I would like to be able to keep my add-on enabled. Please add this to the bug list.

Exact same problem here, same version Kutools 18 and Excel 16.
Have been unable to work as expected with my legit licenced Kutools for a few weeks.
We need a fix to that soon!

Hello,
Please try to contact us with your order information via sales@extendoffice.com.
Thanks in advance.

I will contact you with this information, but what does that have to do with the issue? I can answer, nothing!

Hello,
Please update to the latest version 19.00.

Hello,
Please go to download and install the latest version 19.00

Hello,
Please try to download and install the latest version. If want the support urgently, please contact us via email.

Hello. I downloaded 19.00 and installed. Restarted Windows. Opened Excel and registered. Restarted again. Same result - crash if I try to open a file directly. If I open Excel, I can open a new blank document, but I cannot open an existing file without crashing.

Hello,
Only one existing file or all existing files?
Where are those existing files? Have you stored them in the OneDrive local folder or Google Drive local folder?
Thanks.

Hello. I downloaded 19.00 and installed. Restarted Windows. Opened Excel and registered. Restarted again. Same result - crash if I try to open a file directly. If I open Excel, I can open a new blank document, but I cannot open an existing file without crashing.

I am having the same issue. I had no problems with 18 but since I installed 19 I have to disable it to use Excel (16/365 64bit version). Opening an existing file (not just one - every one I've tried) will either freeze Excel on the splashscreen or the splashscreen will show "Opening: KutoolsforExcel.xlam (100%)" but will stay that way for as long as 5 minutes before opening.

If I am able to get into Excel it will freeze pretty quickly - especially when using cut&paste. When Kutools in disabled I don't have any problems.

When I first had problems after upgrading to Kutools 19 I uninstalled both Office and Kutools, deleted all folders and did a clean install. I still have the same problems.

Hello,
Please try this version

https://download.extendoffice.com/downloads/Kutools-for-Excel/beta/KutoolsforExcelSetup.exe

Thanks in advances.