After installing Mountain Lion the Mail app is not working anymore. It gives an error message "Mail cant open because you dont have the necessary permissions to change the folder where it saves information. Mail stores information in /mail/Mail. If this folder is on your computer, use the Get Info window in the Finder to change your permissions for this folder to Read & Write. If this folder is located on a network server, contact the server administrator. After your permissions are changed, open Mail again." I store my e-mails in an encrypted file container (encrypted with TrueCrypt). In order to access the e-mails, I need to mount the file container, and it appears as mounted image in the Finder. I have created alias for the folder ~/Library/Mail/ so it refers to the folder /Volumes/mail/Mail/ on the mounted image. I checked the permissions of the mounted image and the folder Mail in that image - both have read and write permissions. I have logged in as admin. To check if Mail works at all and if I should rebuild the whole local e-mail storage, I copied the Mail folder outside the encrypted image to ~/Downloads/ and then the Mail app works fine and the e-mail storage also seems to be intact. Then when I put the folder back on the mounted image, the same problem returns. I have already tried reparing disk permissions and have verified the hard drive and the image with Disk Utility. The weird part is that there were no such problems with Lion yesterday. Any ideas what has changed in Mountain Lion vs. Lion to cause this and what might be the solution? If it gives any clarity to the situation, I am running late 2011 13"MBA, 1.7 i5, 4GB RAM, 128GB SSD. Thanks in advance!