Project Upgrade to new Unity version. Does it have to be so painful?

I had numerous issues trying to upgrade the project from 2019.2 > 2019.3 when using unity hub and selecting new Unity version for the project. Then I tried creating a new empty project in new version and copying over assets, . Got also tons of errors and lots of broken references inside of the Prefabs, but I managed to fix this by reimporting all the packages and plugins and duplicating some of the existing problematic prefabs and relinking them.. took me a whole day to fix all those issues.
Is there a recommended way to do this? so I can avoid wasting so much time? I need to upgrade again , do 2019 LTS soon, so any advice would be appreciated.

 

Lots of different errors:

there was also a problem of linked variables for script inside of prefabs that just magically disappeared once the prefab was instantiated during runtime... that's demonstrated in this video:

I just really want to avoid all of this for my next upgrade (to LTS).

 

Using Hub was OK, I just selected the project to be opened in the new version of unity I downloaded (via using Hub Install section). It was after the project was recompiled and opened I had like 500 error messages.
Tried to fix it inside of this project (reimporting the packages, using Google play resolver etc) couldn't do it.
So then I tried going via new project in new version route and copying over the assets, which was the route that worked at the end, but still tons of errors to fix, and those issues with broken prefab script references (that only appeared at runtime)

 

To get it working again, I used the approach of creating new blank project in v 2019.3, then copying over assets, reinstalling all the packages and plugins I used, trying to resolve all the missing / broken prefab refs by duplicating prefabs and relinking them. it was all quite slow and painful process, a day's worth of work altogether.

I'd rather document / bug report the upgrade from 2019.3 to 2019 LTS as that previous upgrade happened weeks ago.

Please let me know what will you need to be able to debug this acurately. I was going to screen cap the whole process anyway, but I assume there will be a bug log report? Maybe I can clear the log before I do upgrade, etc?

 

I'm assuming you would want to have project in the current state before upgrade correct?
I can provide it (I'll zip it and put it on my google drive) but don't want to link it here, if that's ok.

 

great, thank you Karl, will do (if I encounter issues with the upgrade again, of course)

last question: Will those attachments be visible to the public?

 

@karl_jones I've discussed this with some people and they recommended I erase my library folder before performing an upgrade. Is this OK / safe to do in your opinion?

 

I've just upgraded!
Deleted the Library folder in forehand, and I think it went OK, will need to do a bit more in depth testing obviously to check everything.

However, spotted 2 issues so far:

1) I seem to have lost all my mobile /screen resolution presets? There were quite a few and now they are all gone apart from maybe 1080p one. I made a backup of a project folder before, is it possible to copy over a file maybe that will give me back those resolution presets?

2) Collab is giving me the message I need to update, because "there are server changes" ?
but when I click on Update I get this (very scary) message:


Not sure I should click on "Yes"?

 

Thanks for the advice, Karl.
Turns out I didn't actualy loose those presets.

What happened was, after upgrade to 2019 LTS, the build target got switched to PC for some reason?
After I switched to Android I got all my presets back.