Not alle Collections are migrated to Lightroom

[Friendly_Whirl6C1C]

I went through the migration, but had to restart some times- as PC  hang a few times. Finally the migration said it was Complete. I have the photos in Collection migrated but Collections where the were are gone/missing

But; 

I have a lot of Collections that was not migrated.   I cannot restart migration again.  Or can I??

Can I rebuild(aka reindex)  Collections only?

How to rebuild Collections agian, or 

[Friendly_Whirl6C1C]

So issue is that Collections was not transferred/migrated as Albums.  

[Aleke · Accepted solution]

Hi @Friendly_Whirl6C1C, welcome to the community!
Just to make sure I understand correctly, do you mean all your photos migrated but the folder structure didn’t carry over? Or are some folders and their photos missing too?
For help with migrating from Lightroom Classic to Lightroom, you might find this resource useful:
https://adobe.ly/4iK1iMF
Thanks so much!
Alek