how to find a list of what apps DO Not work on catalina from high sierra

Yes, any apps which have not been updated to 64 bit compliance will not work after an upgrade to Catalina. The easiest way to see if your currently installed apps are compliant is to do the following. Open the About This Mac link under the Apple logo. Next, click on the System Report button. That will open a window. On the menu on the left, under Software, click on Applications. It may take minute or so for the next window to open, so be patient. This window will list all of your installed programs (apps), including the version of each one. If I remember correctly, in older operating systems, there is also a line which lists whether each app is 32 bit or 64 bit. This will tell you which apps will no longer work under Catalina or Big Sur. They must be upgraded to be used after an upgrade to Catalina. Often times there will be a cost to do so. I hope this addresses your issue.

Anything written using 32-bit code won't work. For a specific list, click here.

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