i was using the AUR in kde normally before
now i switched to xfce and i enabled the AUR , but it doesn’t work
i dont find any AUR packages in the “add/remove software” GUI app
and even in the CLI i can’t find AUR packages
( btw there is no # before the EnableAUR in the pamac.conf file , so it is enabled)
what i wanted to download is scheme48 package but i can’t find any AUR packages anyway and i can’t download them
So you actually have a problem with pamac. No idea there, but until you find what is broken, you can use another helper. Install yay, if you need a gui also octopi. I assume you already have base-devel.
p.s. i edited the title and tags. AUR of course works with xfce. It does not work on your machine 
How did you switch to Xfce? Switching desktop environments isn’t as easy and straightforward anymore as it used to be, and therefore, it is most likely that you’ve done some damage to your pamac configuration in the process.
I am on xfce, no problem in pamac with AUR that proposes scheme48.
Check in Preferences, 3d tab that AUR is enabled (and updates is not), then update databases (in menu).
A fair point. I hope switching means reinstalling. Otherwise you can run into problems. Especially if you did not made a new user with the new DE, the breakage is a matter of time.
i uninstalled the old root partition , and then installed a new manjaro with xfce (without deleting my root and swap and home partitions)
i did it , and it didnt work
thanks , i will try it
Then the problem is most likely located in your home directory. I would recommend deleting ~/.config/pamac/config.
now i tried it
it didnt work
in /var/tmp/pamac/dbs/sync/, delete all files then start pamac. It will reload dbs , then check for your scheme48.
it didnt work
Then create a new user and check with it whether you can have pamac finding your package.
it didnt work too
thank you for your time
If you deleted the config, it defaulted to AUR being turned off. Check the settings.
However, if I understand you correctly, a test user with vanilla settings also have non-working AUR in pamac, which would mean a deeper problem, unless you have the AUR support disabled there which is the default.
Try pamac search -a 
it says “Failed to read AUR data from /var/tmp/pamac/dbs/sync/packages-meta-ext-v1.json.gz : Error opening file /var/tmp/pamac/dbs/sync/packages-meta-ext-v1.json.gz: No such file or directory”
then it lists non AUR packages
i think there is a messing file in this folder
Just checked and that file is present on this system. I don’t know why that would be missing …? 
no it didnt turn the AUR off when i deleted it
there is /etc/pamac.conf file which contains AUR option
My guess is that you have used sudo with pamac via the CLI at some stage, and now your file permissions are messed up.
This thread should help: