I'm a little late joining this discussion, but it's the closest thing to what I'm experiencing. I have Sketchup Pro 2015. I have some older models I created ten years ago in older versions of Sketchup (not sure which versions), but suffice it to say I can't open them. This is bad because I'm doing a new project for an old client and I can't open my original model. The error message is simply "Failed to Open Model".

Any suggestions?

I prefer the slash at the end of a dimension line. The default is the closed arrow. Once I engage the dimension tool, I change it to the slash, and that's what it shows in the dimension dialogue. However, when I dimension anything, it does it with the closed arrow. I then have to edit each dimension to change to the slash. This is really annoying and I can't find any way to lock my preference in, or even to have it dimension the way I want while I'm dimensioning. I don't have this problem in Sketchup, but I almost never dimension in Sketchup...Layout is the best place to do that, in my opinion. I'm using Sketchup 8 Pro on an XP Pro system.