Develop ""An error occurred when attempting to change modules.""

[dhampny]

I've posted this on the Lightroom Queen LrC forum but haven't gotten a solution yet so am trying here also.

Two days ago, I updated to v12 and occupied myself for awhile looking through photos in the Library, switching to Develop and Print modules but doing no work in either. Just wasting time. I had no problems. Today, I opened the same catalog , selected a photo and tried to go into Develop but got the "An error occurred when attempting to change modules." I tried to quit Lightroom and it hung up so I had to Force Quit it. I opened it again, changed my Preferences Performance tab from Custom/Use GPU for display to OFF but got the same error message when I attempted to open the Develop module. (BTW, I can open the Print module without a problem.) Tried to quit, Lightroom hung and I did a Force Quit again.

I updated to v12.0.1 but had the same problems. Using Creative Cloud I uninstalled and reinstalled LrC but still had the same problems. I created a Test catalog but couldn't import an photos because there wasn't an Import button, only the Export button. Tried to exit but Lightroom hung again and needed a Force Quit. I rebooted my Mac, opened Lightroom, created another Test catalog but still had the same issues: no Import button, I get the error message when trying to switch to Develop, and Lightroom hangs and I must do a Force Quit.

I'm using a 2018 Mac mini, 3.2 GHz 6-Core Intel Core i7, 32GB memory, the internal Intel UHD Graphics 630 1536 MB card (but I have Use Graphics Processor now turned Off)

Today, I manually uninstalled the Lightroom Classic application and deleted preference files and all my catalog files. I uninstalled Creative Cloud using Adobe's uninstaller. I downloaded LrC (which brings Creative Cloud with it) and reinstalled LrC. So, I thought I would be starting over again with a completely new and clean installation but when I open Lightroom there still is no "Import" button, only an "Export" button which is, understandably, greyed out. I don't mean that there's an Import button but it's greyed out, the button doesn't exist on the Library screen. And when I try to quit LrC it still locks up and I have to force quit it.

Today, I've also run OnyX and reinstalled mac os Monterey but Lightroom is still giving me the same problems.  Attached is a screen shot of the Library view.

Does anyone have any ideas what is causing my problems and how to fix them?

David

[dhampny]

I don't know why the title of this post was changed?  I wasn't having problems with the Print module at all.  It was the interaction between the Library and Develop modules, and Lightroom itself in general.

In any event, I've found out what my problem was.  For the past three weeks up until earlier this week, I had been using and learning ON1 Photo Raw 2023.  I kept having problems with it, primarily repeated crashing.  Their tech support were very responsive but hadn't been able to solve the problems so this week I removed the program from my computer.  I also had 5 of their plugins from version 2022 that I planned to use with LrC.  A few minutes ago I decided to delete all of those just to see if that made any difference with the problems I was having with Lightroom.  Once they were gone my problems went away.  LrC appears to be operating completely fine and normal now.

[dhampny]

I've posted this in the Lightroom Queen forum also.

I wanted to update and correct my prior post and what I thought was the solution to my LrC problems. A couple of days after this post my Lightroom problems all reappeared, so deleting the ON1 applications was not the solution. In fact, I now feel that what caused my LrC problems (more on that below) also caused the problems I had with ON1.
I powered down the eGPU, disconnected my monitor and connected it to my Mac mini to begin troubleshooting. First, I created a Test User admin account and booted into that account but my LrC problems remained. Next, I booted up in safe mode and Lightroom began working properly. The Import button was back, I could switch modules without an error message, I could open Preferences, and I could shutdown Lightroom without having to do a force quit. So I rebooted normally and removed any applications that opened on Login, but my Lightroom problems returned. I then carefully disabled or removed certain select LaunchAgent and LaunchDaemon applications but that didn't help either. I reinstalled mac os Monterey but that didn't fix the problem. I then decided as a last resort that I would erase my hard drive and do a clean install of mac os. In preparation, I disconnected my external hard drives. Then I unplugged the Thunderbolt 3 cable that connected my Mac mini to the Razer Core X eGPU. I don't remember why I decided to launch LrC at this point but I did and it worked fine, with none of the problems I had before. I went to the local Apple store and bought an Apple Thunderbolt 4 cable and reconnected my Mac and monitor to the eGPU and Lightroom has been working normally for a week now.
The cable I had been using was an "Intel-certified" Thunderbolt 3 cable. I don't know why using an Apple cable made the difference. In addition, I don't know why the non-Apple thunderbolt cable was still causing a problem when it was connected between my Mac and the eGPU, which was turned off.
But, all is good now.