Photoshop has become a nightmare in my class

Last year my 7th and 8th graders used Photoshop 2017 without any problems.  Unfortunately my computer guys deleted that version of Photoshop and loaded Photoshop 2018 onto my student PCs.  We started the Photoshop lessons three weeks ago and we have not yet finished the first one-day lesson.  Our experience with Photoshop 2018 was plagued with constant memory errors; errors we never experienced with Photoshop 2017 last year.  Some students received memory errors when they tried to open Photoshop, some had errors when they tried to use the paintbrush, or other tool, and some students had errors when they tried to save their final drawing.  Oh yes, we also had errors importing a picture of a leaf (jpg format) that we used last year.  This error has occurred with a lot of jpg pictures my students have tried.

Last weekend my IT guru reloaded Photoshop 2017.  What changed in Photoshop 2017 over the year.  My students had no problems with the version of Photoshop loaded around January of 2017.  Today my students were excited to be able to use the same product we used last year (or we thought we used last year).  Once again many of my students were plagued with memory errors and with being unable to import the starting picture.  I was able to change the baseline picture but I cannot seem to get around the memory errors.