Upgrading Excel 2010 add-in to office 2016

Question

When upgrading to Office 365 / Excel 2016, I found that it was extremely slow to open, and even slower to close: Waiting 20-30 seconds to open to a blank workbook, and taking over a minute to close-down excel.

My investigations showed that the problem was an Office 2010 add-in. The add-in is a custom one that I wrote a few years ago - it was created with the help of the CustomUIEditor tool (to allow me to create a Ribbon for my add-in) - ie it is a .XLAM add-in, not a COM one.

After lots of googling, I can't find much about add-in compatibility between Office 2010 and Office 365. The CustomUIEditor that I used previously has not been updated in around 10 years, and I can't find a useful alternative.

Has anyone come across a similar issue before (and solved it?) Do I need to recreate the add-in as a COM add-in?

Answer 1

OK - thanks to Siddharth for taking the time to respond. I managed to solve my Excel issue, and in the end it was unrelated to the add-in (even though disabling the add-in did improve the speed that Excel opened and closed).

The issue was related to a lot of old files in my %appdata%\\roaming\\microsoft\\excel\\ folder. Lots of corrupted files that it was trying to read / write back when I opened or closed excel. I deleted them and Excel is now working properly.