P: When trying to add files to Collections I get this error: ?:0: attempt to compare two nil values

I have also recently installed LrC 10 on my PC and found that when I went to add images to a target collection or just drag and drop into a collection, I get the following message, An internal error has occurred: ?:0: attempt to compare two nil values. This is really frustrating me as I'm not a computer buff and therefore I thank you for any help. I understand from earlier post that Adobe are aware of this issue and working on a fix?

Why conversations get merged: https://feedback.photoshop.com/conversations/lightroom-classic/lightroom-auto-import-to-folders-organized-by-date/5f5f44f14b561a3d422ab0ba?commentId=5f5f48984b561a3d422bdf45 

Thank you John R Ellis! That worked for me!

I've not. I will pick this up again in the morning and see how it goes. Thank you for your help

Did you try this one, recently posted: "A work around. If you make a selection and then hover over the destination collection folder, right click and Add selected photo to this collection. It works for me after I get this error."

Thanks John.

I tried this before posting with no luck

Try the workaround at the top of this thread:

https://feedback.photoshop.com/conversations/lightroom-classic/lightroom-classic-when-trying-to-add-files-to-collections-i-get-this-error-0-attempt-to-compare-two-nil-values/5f9091ea35f40c2520b9ecc4 

This issue has just happened to me now. I was using quick selection fine at 13:30 today and now 20:15 it's bringing up this error.

I have made no update today.

Any suggestion on a fix? 

I get this error (An internal error has occurred: ?:0 : Attempt to compare string with nil) in the Develop Module (after completing edits using a preset) when moving from one image to the next in the "film strip"

Try resetting the preference file: 

A Preference File will survive a Lightroom uninstall/reinstall. Sometimes weird behavior is corrected/cured by resetting the preferences.

Reset Procedure:

1. Close Lightroom.

2. Hold down [Alt/Opt]+[Shift] while restarting Lightroom.

3. Overwrite the Preferences when prompted by the dialog.

4. Close Lightroom.

5. Restart Lightroom.

Does the behavior continue after resetting the preferences?