After Catalina upgrade, backup not working

Pamela Veenstra Said:

"After Catalina upgrade, backup not working: I used Time Machine fine under Sierra. After Catalina upgrade, TM prepares endlessly, but doesn’t back up."

If it is repetitive...

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Reset SMC and your NVRAM Thrice:

USB port settings may need to be reset. Sometimes, changes (i.e. Update Installations) are made, and then settings (i.e. For USB Ports) become manipulated, technically. So, reset both. Note that this may take three tries just to reset them successfully. It may take some time to perform this. So, be certain you have the time to do so.

Use these Links:

• Reset NVRAM or PRAM on your Mac - Apple Support
• How to Reset the SMC of your Mac - Apple Support

You may need to unmap and remap the Time Machine backup with Apple menu -> System Preferences -> Time Machine.

You may have run out of space.

Also Catalina is not compatible with numerous older apps.

Have you made sure your entire inventory of apps and drivers are 64 bit?