How to modify an existing assembly in a new folder to get something new ?

Until my last using of SW :

when I copied an existing asm in a new folder, I got msgs saying that part1, part2, .... partn were missing, and the program asked me if I wanted to make a manual research.

That was very useful, if I wanted to create a new version of this assembly.

But today, I tried this tip, and the program finds every part of the asm, the asm being in the new folder, when all parts stay in the "old" folder.

What option I have to check, to get the previous msgs, so the program finds only in the current folder, and not in the old ones ?

Tx for your help

SolidworksAssemblies