We have a large enum in out application, with over 7,000 items.
This was causing sporadic crashes in Visual Studio 2005 until we reduced the items in the enum down to about 1,200.
The newer versions of R# crashed more often than the older versions.
Please look into what could have caused this problem, it did not affect every place we referenced the enum, but it was in pages and in the code behind.
I do not have a concrete example to post.