home for arch & debian - problem with uid

My arch user (william) have uid 500
and today I installed debian and mount /home partition and I add user with this same name as user from arch ( I would like have this same settings for all programs)

but debian user has uid 1000 and now I can't open my home/william directory...

Question is simple: How set again that /home/william is directory for william with uid 500 ( arch william)...?

Debian by default sets all (non-root and non-system) users to be uid 1000+.

Your options are to either set the user to be uid 500 in the /etc/passwd file, or chown -R <user>:<group> /home/user to change the files to the new uid.