10.15.1 will not update

Do this:

Reboot your computer into Safe Mode. While in safe mode try re-doing the update.

If the does not help, then do the following:

Reinstall El Capitan or Later Without Erasing Drive

Please be sure you back up, if possible.

1. Restart the computer. Immediately, at or before the chime, hold down the Command and R keys until the Apple logo and progress bar appear. Wait until the Utility Menu appears.
2. Select Disk Utility and click on the Continue button.
3. Select the indented (usually, Macintosh HD) volume entry from the side list.
4. Click on the First Aid icon in the toolbar. Wait until the Done button activates, then click on it.
5. Quit Disk Utility and return to the Utility Menu.
6. Select Install OS X and click on the Continue button.

Upon completion retry your update.

Hello Kappy - the Safe Mode link does not seem to work. Can you please update or provide some information? I am getting errors on my 10.15.1. upgrade on my iMac as well. I click on re-start upon prompt and it goes to Installing mode for ever. I have to then do a hard re-boot.

Sorry, apparently Apple replaced the link with a different one: Use safe mode to isolate issues with your Mac - Apple Support.

What errors are you getting? Please be complete.