I did switch it on now. It took near to forever (90 mins) but it is working now, without trouble at all. Only annoyance is indeed these messages about recovering drivespace. I did some trial & error on it, and I found out that it wants to do this as soon as the used space in your homedir is less than the size of the diskimage it is using to store your homedir in. In other words:
- Let say you have 235 MB of data in your Homedir
- You convert it to FileVault. This creates an encrypted disk image of exactly 235 MB and puts all your files in your homedir in
- You add 15 MB of data to your homedir. The FileVault diskimage is automagically extended to hold this extra data, so the disk image is now 250 MB.
- You remove 2 MB of data from your homedir. When you logout FileVault whines about recovering data. What is going on?
- your filevault disk image is 250 MB
- the size of the data in it is 248 MB
- the filevault software calcs: 250-248=2, which is > 0 --> so we need to recover something.
Sounds like Apple needs to work on some improvement here. I think it is ok if the 'delta' is 50 MB or more that it suggest to recover. But not for 2 MB, that is ridiculous, since you work on files everyday. You don't want to recover filespace everyday.
Maybe for people working with large files everyday this limit should be even higher. Apple should make it a preference which a user should be able to set for him/herself.
For the rest, FileVault works like expected. It is as fast as without, no glitches noticable. And it gives me some nice feeling of extra security

. (which is probably ridiculous because if it gets stolen (heaven forbids!!!), the thief won't be interested in my personal crap, he just wants the hardware. he will probably format it right away to erase tracks...)
Anyway, just in case the thief is more creative, FileVault gives some extra feeling of protection that I like.
Don't forget to make regular backups on CD's or so....