no problem selecting rotated guides here, zoomed to +1000%, using CS5 on Win
Have you tried to reset the preferences (lose down Illy and press Ctrl+Alt+Shift/Cmd+Option+Shift during startup (easy but irreversible), or Move the folder with Illy closed (more tedious but also more thorough and reversible))?
3 years later, I'd like to "bump" this post. I have tried resetting my Illustrator prefs. I can grab guides at 300% zoom, but not at 1000%. This is ridiculous, since I find that I have to do significant zooming in to get Illustrator to snap to the right objects correctly (often it pretends that it is snapping to the anchor, but if you zoom in, you see it doesn't actually do so. Would be good if they fixed this. It's been ongoing and obviously something the have neglected.
Currently having the same problem, I can't seem to reliably select rulers when I'm zoomed in more than 300%
This seems to be appearing in multiple threads in the forum, and I have been having this problem for the past few years on multiple versions of Illy. I appreciate all the various suggestions being put forward by some of the veteran Illustrator users. yet so far there has been no input from Adobe.
While this might seem like a small problem of little importance, it has the potential to render more complex and detailed projects impossible, and it seems to be affecting quite a few people.
So I would love to see Adobe addressing this problem directly.
I would suggest to report it as a bug and mention this forum post.
It is easy to replicate (although you sometimes have to zoom in more than 300% to get the problem).