My first thought was to keep everything on server using IMAP to view whats there. Thats how you sync between different devices and OS. Second thought was to use an area accessible from both OS to put a single profile in. Then in profile.ini point to this area.

EDIT the last thought might be unusable as add-on can be specifically for only one OS.

Gnospen: Thank you for your help. I understand your second suggestion. I have tried that but find that when I put a path in the profile.ini file it does not want to follow the path= . It only seems to like path=Profile/... Not the full path that I enter on the Windows side. I think it works on the apple side. I will check again. I have just been busy.

Yes it appears the the Apple side will follow the path but the Windows Profiles.ini file won't follow the path I enter. On the Apple side I can not see some of the folders so I can't just direct the path to the Windows side path to Thunderbird profiles.

Seems weird to me.

Have you set IsRelative to false and then entered a full absolute pathname, with backslashes, for the Windows variant?

I presume in both cases there is a legitimate pathname to access the common shared folder. I'm not familiar with Mac OSX filesystem conventions, but whatever pathname structure you'd use to navigate to the shared folder needs to be stored in the relevant profiles.ini file.

You seem to have overlooked the best OS of all, Linux.  ;-)

Gnospen made a valid point. You probably can't simply share a profile that contains the Lightning calendar. Windows and OSX each need their own variant of this addon.

Another thought, If you point attachment settings / server settings and local directory under message storage to your shared area. That would leave calendar in both profiles, so you need to use a cal over network, like gmail, and synchronize. Then there is the address book... I don't know how to have it somewhere else but in the profile. (LDAP-server is hard to update). One way might be to keep it in your shared area and download / upload every time changes has been made.

I am not normally in favour of using the Local Directory to split out the individual message stores, as it makes management of the profile rather more difficult. But in this case it may be the least worst option.

I don't try to share profiles on this way. I use IMAP for mail, and Google Calendar and Google Contacts, so I'm using "the cloud" to operate a shared resource.

If you're Google-phobic then there is an addon that uses a folder in an IMAP-connected account to share address books, which works tolerably well. I haven't found an equivalent for calendars, though some report using an ICS file as a shared resource works for them.

OK after a lot of trying to set a path in profiles.ini I did two things.

1. I got a program that will read NTFS files.

2. a. I was able to make access to my Windows directories and files available in OS X.

b. Then I used profile manager to make a new profile and changed the path to the same profile in Windows.

So now it appears to work. I saw an unread email in the OS X side. Then went to Windows and clicked on it. Went back to OS X and it had been read.

So it seems that what I needed is working. I am not concerned about calendars. The left side bar that holds all of my folders and emails does not change concerning what I have selected but I think (have not tested yet) that the emails will be the same because the folders are.

Thank all of you for your gracious help.

All the best,

Rick

Addition/correction to my last. The changes made on one side for opening or closing folders ARE reflected in each side.

This is great!

Thanks again!

I must warn you that add-ons are stored within the profile. They would be read by both OS.

Thank you Gnoxpen. However the NTFS read program is not an add on to Mozilla it is a separate program. This one happens to be Paragon NTFS for Mac OS X