2 full days (and counting) opening project with 2019.3

I have a large project, and decided to see how it will run in 2019.3. I've opened the project and it asked if I wanted to convert the project to use the new Asset Database V2, so I said yes. Is this process very slow for everyone? Because this conversion process has been running for 2 full days so far, and I have no idea how far along it is. What seems to be taking most of the time is the processing of .fbx models. Each one of these seems to take 30 seconds, or a minute (or possibly longer, I haven't times it), and I have many thousands of .fbx files in my project. I guess I'll let it keep running, and see what happens, but I've never seen this kind of thing when using new versions of Unity. In the past,a full re-import has taken (if I remember correctly) between 1 and 3 hours.My guess is that converting to the Asset Database V2 is just something that can take awhile to complete, but perhaps the process isn't optimized.

 

Same thing occurred for me. I was stuck on iteration X for about 1 hour before I intervened. I had to force close the Unity process tree in task manager and fire it up again. After doing this it worked for me, although slow moving. Took about 3 or so hours total. It can get stuck on large meshes (we use custom mesh terrain which is segmented by about 100 submeshes per tile) these took about 20+ minutes per tile. Better verbosity is needed with this because right now it is unclear if the process is still going or has hung up.

This new thing they show (iteration XXXX) along with importing dialog pops up very often even after import sometimes for minutes, sometimes for brief 5 - 10 seconds upon many actions in the editor including shifting focus from code editor back to Unity. It quickly becomes a nightmare as it is popping up anytime anything in the project tab is changed. The entire editor in general feels very sluggish and is slow to respond with anything in my project. My project is very code heavy but very light on assets.

 

Did you remove the Library folder before upgrading? (and back up your project)

 

The problem sounds like this report:
https://forum.unity.com/threads/case-1202254-project-does-not-open-infinite-importing-cycle.786308/

 

I also have the issue where .fbx files takes forever to Import. Had to delete all fbx files in our project today just so I could open up Unity.

I got everything imported on a separate PC tho. And what usually takes a couple of minutes, now takes hours. I didn't get any infinite import loop however, everything completed on "Iteration 3". So probably the extremely slow .fbx import is a different issue from the infinite import loop one.

 

Just figured out that the slow import of .fbx files, is only slow if it has to import while opening up Unity. For instance if you've deleted your Library folder as you often need to do.

So a workaround you can do is:

1. Delete all your .FBX files
2. Open Unity
3. Undo the delete

And then It'll import them quickly, and you can start and reverse all the damage done from deleting the fbx files.

 

FYI, the process did complete this morning, so I guess the total time took around 3 days or so, but I didn't time it exactly. After the long wait, the project did open, and I was surprised that the project seemed to run ok. Usually There are a lot of obvious problems I need to work through when upgrading to a new version.

Regarding APSchmidt's question, not I didn't remove the Library folder, and yes I did back up my project first

 

2020.1.2f1 Deleted Library and reopen, now at 80+ hours...

 

After some trouble with our git, we decided to re-clone the repository. Here we changed the path locally to another drive. After opening Unity, it was importing for two whole days and still no end in sight.

The solution to our problem was, to cut & paste the whole Dependencies folder, or its content out of the projects folder. The Dependencies are Assets from the Unity Asset Store, most of them being with many FBX files for which Unity took hours to import.
We opened up Unity again, which took like 10-20 minutes at most now, since Unity only needed to import the Standard Assets. After Unity had opened up completely we just placed the Dependencies back into the project folder, while Unity was still running. Another few minutes of import, maybe 5 or so, a Unity restart and Unity was back to normal!

We hope this is of some help to those who are still struggling with import problems.