Unable to change serial number. Adobe Acrobat Pro 2020

[Steven23640747secf]

I am assiting an end user. They are a non-profit organization that received 3 product keys for Acrobat Pro 2020 from TechSoup. Upon booting up Acrobat, I am met with an activation prompt to either change the serial number or stating that I've deactivated another device using the same serial number. When entering the newly provided key, nothing changes and the promt will come back (see below). 

I have tried uninstalling, rebooting, and reinstalling all Adobe applications from the device but am still getting the same message with the same serial number. Is there a registry key I can edit to make the serial number change?

Thanks

[Brad @ Roaring Mouse]

Deactiviating is not the same as uninstalling. Consequently, uninstalling does NOT deactivate. For Acrobat, you deactivate by signing out/deactivating under Acrobat's Help menu. If you are getting this notice, whether you did it or not, someone has already installed and signed in on two other devices. If you have access to even one of these other two, you can deactivate it and then continue on installing on the new computer.

Now, if you've never used any of these codes before, then something is up. That's an issue for this Tech Soup thing.

[Dave Creamer of IDEAS]

A single user/serial number is allowed two activations. For example, in my case a tower and a laptop. The software must have been installed on two systems already. 

A few possibilities could have happened:

• Someone at the non-profit installed the software on two computers already. The license is for a single user; some use the two activations for two separate users, which is not allowed.
• A computer crashed and was reformatted before any software could be deactivated. A reinstall would have taken up a second activation. 
• The software was uninstalled but not deactivated.
• The company re-sold the serial numbers. (Unlikely, since it appears that TechSoup is a legit company.)

You will need to contact Adobe support and ask them to reset your activations.