Indexing mail - mail not responping

I have a problem with errors in my Mail index, with folders showing numbers of mails that are incorrect. I have tried rebuilding each of my (too many) mailboxes which did not solve the problem.

I am now trying this:
*I Quit Mail
*I removed the Envelope Index files from ~Library/Mail/V2/MailData
*I restarted Mail

I get a screen saying "Preparing to import messages" but the graphic is not moving and both ForceQuit and Activity Monitor say that Mail is not responding. Activity monitor shows that the % CPU, CPU time, and threads listed for Mail are changing. This suggests to me that something is actually happening, and that when Mail is done indexing it will not look as if it is not responding.

If it is not responding because it is busy rebuilding the index, I am happy to let it go. But if this is not what I should expect - if it is truly stuck and not rebuilding the index - then I am at a loss for next steps.

I am using Mavericks (10.9.5) and am trying to fix as many issues like this as I can before I upgrade to Yosemite in a couple months. I want to avoid being unable to function in the new setting...

Would love suggestions, or experiences like this...

P

Indexing issue: resolved

OK, it appears that what happens is:

*ForceQuit and Activity monitor say Mail not responding.

*After a long time, the three Envelope Index files in ~Library/Mail/V2/MailData ultimately stop changing and Activity Monitor stops showing any CPU use

*Then one needs to force quit Mail and restart it. Perhaps more than once (It took me 3 times.)

*Then there is a new and accurate index and Mail is noticeably faster.