I've installed both Lightroom CC and Lightroom 6 on multiple machines. I'm experiencing the following difficulties with both.
1. When I exit from Lightroom CC or Lightroom 6 (Yosemite 10.10.3), the program appears to exit, but doesn't actually close. I have to use either the activity manager or CTRL-ALT-ESC to "Force Quit".
2. While in Lightroom CC, histograms do not appear in the histogram box either in the library or develop module.
3. On many images, the preview will not load in a reasonable length of time (5 minutes).
My hardwares are: 1) a Trash Can Mac Pro (2014) with 32 GB RAM, 6 cores, 3.5 GHz per core, and the 1 TB flash drive (0.7 TB free).
2) 2011 (Late) Mac Pro, 3.4 GHz Quad Core, 32 GB RAM, 2 TB Hard drive (1.8 TB free).
I've tried uninstalling, followed by reinstalling both programs, I've redownloaded the Lightroom 6 and Lightroom CC programs directly from Adobe. I've rebooted my machines. I've signed out of the CC and signed back in.
Right now I'm mostly frustrated by the inability to use the program for anything function.