Since having switched from Lightroom 5 to Lightroom CC 2015.* (instead of upgrading to LR6 standalone) the app regularly crashes upon one of the following actions: switch to another picture (in "Develop" module, not in "Library" mode), resize but sometimes with other actions like sharpening, dust removal, increase clarity etc. It doesn't crash every time but only after having edited 3-5 pictures beforehand. That is, it never survives editing more than 5 pictures.
I am observing this behaviour on my two iMacs (both Retina 5K, 27", late 2014 with 4 GHz Intel Core i7 and 16 GB RAM), one with an AMD Radeon R9 M295X 4096 MB GPU, the other with an AMD Radeon R9 M290X 2048 MB. On both machines, Mac OS X 10.11.4 (El Capitan) is running with the latest system updates and with (now) Lightroom CC 2015.5.
The crashes happen independently of enabling or disabling the GPU OpenGL usage.
I see the crashes more often on pictures with large RAW sizes (i.e. Nikon D800E raw editing) but also when editing iPhone pictures or Raw material from Panasonic FZ1000.
I've tried to work on freshly created LR catalogues, too. No effect though.
I've also tried waiting for the next LR update over the last months, but none of them helped. Only the first update somehow reduced the number of crashes.
My current workaround is backing up the catalogues as often as possible and to manually restart LR after 2-3 picture edits (or to just restart it after a crash). I've also started sending automatic crash reports hoping that some poor soul on the other side of this forum is seeing them and gets alerted.
As this is no optimal working condition, I ask the forum members and the Adobe staff: What else can I do?
Sorry for the duplicate post. I am closing this one.