ALM 12.20 Upgrade from ALM 12.01 Error: ALM is installed on this machine
Hope you are doing great today.
According to the issue, could please check if you can do the steps in the below KM:
https://softwaresupport.hp.com/group/softwaresupport/search-result/-/facetsearch/document/KM01380589 - How to uninstall ALM 12 manually in windows
Hope it helps.
Krystal Mata U.
HP QC/ALM Support Team
(If this post or any other post helps to resolve your issue or query, please mark the thread as solved)
(Posts and opinions made here are my own and do not reflect the opinions of my employer HP in any way)