I have been using happily QGIS for about 6 months, in the last week it has suddenly got much slower when generating an atlas using print composer.
I am running QGIS 2.10.1 on a PC laptop (Windows 7, core i7 2.4GHz with 16GB RAM).
The projects I've been working on have about 10-15 shapefiles (100-200MB each) and around 10 print composers.
Rendering in the main screen doesn't seem to have been affected but as soon as I try and generate an atlas from one of the print composers (even for only one atlas feature) everything is greyed out and 'not responding' for at least 20 minutes. This occurred even when I set up a simple project with 5 shapefiles and one print composer with one atlas feature.
I've tried uninstalling and re-installing qgis but clearly didn't manage a clean re-install as the recent file list is still populated (also, it made no difference to performance). I find it hard to believe my projects can be stretching the limits of the software or my computer to this extent. The one thing I did recently change was I installed the mmqgis plugin but uninstlling had no effect on the reduced performance.
Has anyone had a similar problem with the print composer? and have suggestions as to how to fix it?