Disparition de groupes de pinceaux

j'ai le même problème et suis avec IMAC je n'ai pas windows et cela vient de m'arriver une deuxième fois! c'est une perte de temps

»Hello

I had imported, for a fortnight, new brushes in photoshop and created groups to better organize them (clouds, snow, dust, ...) by theme. I've been using them this way for two weeks, and last night wanting to use one, I realized that all the groups created, and the imported brushes, have disappeared. Only groups of "original photoshop" brushes remained. I had taken quite a while to search for these brushes on the web, download them and sort them by category ... does anyone have an explanation for this disappearance and a solution to "restore" them without having to redo all the steps of this work?

Thank you in advance.«

The preferences might have suffered random corruption.

One reason why one should save one’s cutsomized presets from time to time and back them up. 

Did you store the abr-files you downloaded?

Did you put them into the Presets/Brushes-Folder? In that case they should still be available i the pop-up menu of the Brushes Panel. 

The manual re-organization in Groups etc. will probably have to be redone.