End User is stuck in the Signin / enter SN loop

Hi @good_developer6649,

Thank you for the detailed information. Since you're working with Adobe Acrobat 2020 and are experiencing a persistent sign-in or serial number loop—even after using the Cleaner Tool and reinstalling—it appears that remnants of a trial license or user-specific licensing data may still be interfering.

Please follow the steps below to help resolve the issue:

Ensure the Cleaner Tool fully removes licensing data:

Use the Adobe Acrobat Cleaner Tool, available here: https://adobe.ly/4mD2qTK
Run the tool with administrative privileges. 

Remove Adobe-related entries from licensing folders:

Navigate to the following directories:
C:\Program Files (x86)\Common Files\Adobe\OOBE
%ProgramData%\Adobe\SLStore
%ProgramData%\Adobe\SLCache

Back up and then delete the contents of the SLStore and SLCache folders. 

Reinstall Acrobat 2020 and apply the serial number offline:

Disconnect the computer from the internet.
Run the Acrobat 2020 installer as an administrator.
Enter the serial number when prompted.
After installation and successful activation, reconnect the device to the internet.

Check for residual Creative Cloud or trial licensing:

If the user previously used a Creative Cloud trial, it may interfere with the activation of perpetual license products like Acrobat 2020.
Ensure that the Creative Cloud Desktop application is fully uninstalled and not running in the background. Try CC cleaner tool for this: https://adobe.ly/3Z7D7PA

If the problem persists—even when using another Adobe ID—it is possible that system-level remnants are causing the conflict. As a next step, try creating a new Windows user profile and performing the installation there.
Additionally, try installing other software on the affected machine to rule out image-level issues. Reimagining the machine may be considered a last resort if possible.

Please let us know the outcome after completing these steps, or if you require further assistance.

Regards,