Problems trying to upgrade from Catalina OS 10.15

Before you incrementally upgrade to Monterey you might give the following a try (be sure you have a minimum of 50 GB of free space on your boot drive, more if possibe):

I've had better luck from the Safe Mode because I evidently have some 3rd party software that interferes with the installation so try the following:

#1 - boot into Safe Mode according to Start up your Mac in safe mode - Apple Support.

NOTE: Safe Mode boot can take up to 3-5 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

#2 - go to the System/Software Update preference pane and begin the download.

#3 - run the installer from the Safe Mode.

Really suggest update Catalina at least to something recent as Catalina OS 10.15.1 is well really out dated.

There are many reports of people attempting >>

1 - UpGrading to Monterey with out dated version of older version of macOS and failure have occurred

2 - Jumping from Older Versions like Catalina and Mojave, even if Full Updated and jumping over Big Sur directly to Monterey have also had some success and some failures.

3 - There are reports appearing on the ASC Forums regarding failed installation of Monterey on older Qualifying Apple Computers. In most cases this is related to having a NON Apple Original internal drive ?  

The EFI Boot ROM included in Monterey is verifying for Original Apple Drive and if not found , may Balk or fail to upgrade to Monterey. 

Reports indicate the EFI BOOT ROM is Required to Flash the Computer and is a  requirement for a Successful Monterey Installation.

Please, re-read the original reply.

Incase certain aspects have been overlooked see below and suggestion are supplied.

" Really suggest update Catalina at least to something recent as Catalina OS 10.15.1 is well really out dated.

There are many reports of people attempting >>

1 - UpGrading to Monterey with out dated version of older version of macOS and failure have occurred

2 - Jumping from Older Versions like Catalina and Mojave, even if Full Updated and jumping over Big Sur directly to Monterey have also had some success and some failures. "