Metadata files could not be found

I sync my Unity game between my work computer and home computers via Megasync. Usually this works fine but the other day a few files failed to upload. To be safe, I didn't open my synced project, but copied it into a separate folder as a backup, and then attempted to open the backup. I got the following error 4 times:

 error CS0006: Metadata file `D:/Unity/Backup/Portal Ball Backup - Nov 21' could not be found
 error CS0006: Metadata file ` 2019 - Level Design/Library/PackageCache/com.unity.ads@2.0.8/UnityEngine.Advertisements.dll' could not be found
 error CS0006: Metadata file `D:/Unity/Backup/Portal Ball Backup - Nov 21' could not be found
 error CS0006: Metadata file ` 2019 - Level Design/Library/PackageCache/com.unity.ads@2.0.8/Editor/UnityEditor.Advertisements.dll' could not be found
 error CS0006: Metadata file `D:/Unity/Backup/Portal Ball Backup - Nov 21' could not be found
 error CS0006: Metadata file ` 2019 - Level Design/Library/PackageCache/com.unity.analytics@3.2.2/Unity.Analytics.Editor.dll' could not be found
 error CS0006: Metadata file `D:/Unity/Backup/Portal Ball Backup - Nov 21' could not be found
 error CS0006: Metadata file ` 2019 - Level Design/Library/PackageCache/com.unity.analytics@3.2.2/Unity.Analytics.StandardEvents.dll' could not be found
 error CS0006: Metadata file `D:/Unity/Backup/Portal Ball Backup - Nov 21' could not be found
 error CS0006: Metadata file ` 2019 - Level Design/Library/PackageCache/com.unity.analytics@3.2.2/Unity.Analytics.Tracker.dll' could not be found
 error CS0006: Metadata file `D:/Unity/Backup/Portal Ball Backup - Nov 21' could not be found
 error CS0006: Metadata file ` 2019 - Level Design/Library/PackageCache/com.unity.purchasing@2.0.3/UnityEngine.Purchasing.dll' could not be found
 error CS0006: Metadata file `D:/Unity/Backup/Portal Ball Backup - Nov 21' could not be found
 error CS0006: Metadata file ` 2019 - Level Design/Library/PackageCache/com.unity.purchasing@2.0.3/Editor/UnityEditor.Purchasing.dll' could not be found
     Compilation failed: 14 error(s), 0 warnings

Now here's the odd thing - if I go back to my work computer, the project opens just fine. But the moment I copy it to a USB stick, or let it re-upload and make a copy of it on my home computer, I get these errors again.

So far I've tried deleting my library and restarting but I still get these errors. I've deleted everything but my assets folder but it just creates more errors.

But it still opens fine on my work computer.

I have no idea how to fix this or what to do. Hopefully someone has an idea.