Mojave Upgrade Running Slow (Now Fixed)

A couple of months ago I upgraded to Mojave and my iMac would not boot (2012 Late Model) and when it did, the computer was unusable. After 4 days with Apple support, I one back to High Sierra and did a data migration from a backup hard drive.

Using "About My Mac, Applications" I deleted as many 32 bit programs as was possible thinking this would help the upgrade process. Yesterday I again tried to upgraded my 2012 and later iMac to Mojave and my computer became unusable again.

Here is how I fixed my problem:

I went into a recovery mode (Option-Command-R) and did a total erase of my hard drive. (Prior, I did a full backup on both my time machine and external hard drive just in case. I powered down my hard drive). In recovery mode I did a clean generic install of Mojave with no user data, system configuration or applications installed. Mojave ran fine. I them did a data migration using the apple utility and only restored the system configuration data from my time machine backup. Mojave ran fine. Next, I did a data migration of just applications from my time machine backup. Again, Mojave ran fine. I then did a data migration of my user files from time machine. After completing, I had an exciting moment when everything worked. There were some miscellaneous files that showed up in the data migration utility that could not be identified. I did not load them.

When I purchased this computer, I updated it from my older MAC. I think some files from my old iMac configuration were interfering with the Mojave upgrade. This process only took 24 hours to complete but I am happy to say, I am up and running smoothly on Mojave (so far).

Good Luck.