Re-serializing assets?

I started a new project with a select number of assets that I already bought … seems the program is locked up on re-serializing assets? …I have never seen that before …and this is the second time…

If I close the program not all the assets are there when I restart Unity…

Also it doesn’t seem to matter what assets I try to import …does the same thing…

Try Selecting all the assets which you have imported by selecting all of them and right click, select all dependencies and delete them and try re importing once again.

I had this problem too and the only solution I found was to delete the Library and Temp folders of my project.
It took a while to open up the project again, but at least I was able to work again.