ver 125 was a placeholder for an upcoming release and should not be used. It was never released to general public. The current version is 115.11.1.

So, how do I manage to get the same version on both PCs and migrate all my data? I just d/l a new beta 127... Now what do I do?

FIrst, I suggest NOT USING BETA unless you just want to be part of the test base. Betas have bugs and are not backward compatible with release versions and are not actively supported here except for routine issues. I suggest putting the current release version on both PCs. If there is a compatibilities.ini file, just delete it.

OK, thanks. I have 115 on my laptop but the 125 is on the desktop and the release note says 115 is also installed on it and both say all is current. So, how to I get the same profile on both? 115 won't take the one from 125 and it's the primary I use.

Are you saying both 115 and 125 are on the same PC? Which PC has the desired profile? With that, I can give detailed steps. is this a Windows PC?

125 and 115 were both shown to be successfully installed on the desktop when I looked at the Update History. I had 115 on the laptop, I tried to migrate due to many address book changes, etc., which I've done many times over the years. I saved the profile as it has all my good stuph from years . I now have 127 Beta on the desktop and 115 on the laptop. Neither want my preferred profile. Both are Win. Desktop in Win10, Laptop is Win 11 but they play well and have merged before flawlessly, until now.

what errors do you have when trying to use the preferred profile? Knowing that may prove helpful.

125 and 115 were both shown to be successfully installed on the desktop when I looked at the Update History. I had 115 on the laptop, I tried to migrate due to many address book changes, etc., which I've done many times over the years. I saved the profile as it has all my good stuph from years . I now have 127 Beta on the desktop and 115 on the laptop. Neither want my preferred profile. Both are Win. Desktop in Win10, Laptop is Win 11 but they play well and have merged before flawlessly, until now.

"Your Thunderbird profile cannot be loaded. It may be missing or inaccessible."

That error only means thunderbird can't find it. Let's get it right on the 115 pc and then it will be super easy to get on the other PC. Here are steps for the pc with 115: - exit thunderbird if running - IMPORTANT - copy your profile folder to c:\users\<yourid>\appdata\roaming\thunderbird\profiles - if you to try, open the profiles.ini file (it's simple text) in c:\users\<yourid>\appdata\roaming\thunderbird

  you will see it is pointing to a folder in the profiles folder. overtype the name with the name of your profile and save

- restart thunderbird. if it starts ok, you're done. if not, try again - or do screenshot of the profiles.ini file, a screenshot of your profile

If it worked, here are steps for the pc with 125: - uninstall 125 , download and install 115 from thunderbird.net - exit thunderbird - copy the thunderbird folder on the 115 PC from c:\users\<yourid>\appdata\roaming\thunderbird to external media - paste that thunderbird folder onto the NEW 115 pc at c:\users\<yourid>\appdata\roaming - this will overlay the existing thunderbird folder - now start the new 115 pc and it should start with no problems.

Here's the message I got when I did what you said. https://support.mozilla.org/en-US/kb/unable-launch-older-version-profile Note the "You have launched an older version of Thunderbird"

D/l the new exe from T/net and installing it again.

look for a file named compatibilities.ini in the profile with thunderbird not running and delete it.

Same thing.

I assume 'same thing' means you found the compatibilities file and deleted it with same result? Do you recall what version you were using when you created your preferred profile? Restoring that may be your best bet.

No compatibilities.ini file anywhere. My profile name is dyfldpvx.default-release I changed references in the 2 .ini files in T-bird to match but still get the same message.

what version of thunderbird did you use to create the profile?

It was the 125 Beta but that was never a problem until the 115 installation. I'm stumped and really worried I'm going to lose all my addresses, etc.

David, thanx so much for your efforts. I kept tinkering and I'm now back in bidness, believe it or not! I had v. 115 installed and decided to install Thunderbird Setup 127.0b5 over it, correct the ".ini" files to direct them to my treasured profile and it worked like a charm! I started tinkering with PCs after I retired in 12.1976 as a hobby and still enjoy doing so today at 82 years young. Trying to keep the old gray matter working as best one can. Thank you again.

I'm glad to hear that all is well again. :) Thanks for the update. I remember being 82, and wish you well. :)