Whenever switching catalogs or creating a new catalog in Lightroom 6.6 I get the error "An error occurred when attempting to change modules" shortly followed by a crash of Lightroom. I followed all of the steps in Troubleshooting guide for errors that can occur when you change modules in Lightroom several times, wiping out all of my settings and catalogs, and re-downloading Lightroom from Adobe's web site and reinstalling it, all to no avail — the problem persists.
When reinstalling, I did notice that Lightroom 6.0 does not have this problem for me. However, once upgraded to 6.6, it exhibits this crash. On a lark, I tried upgrading 6.0 only to 6.5.1 — it works and lets me create new catalogs without crashing. So it looks like whatever crash is going on here got newly introduced in 6.6.
I'm using a 2010 Mac Pro running MacOS 10.11.5.
Are there any solutions to this crash in 6.6?
There seem to be some issues with 6.6. Some are even confirmed.
You may want to stick to 6.5.1 and wait until a fix is released.
Before you ask ... No, nobody here knows when this is. Only Adobe knows and they don't tell.