Can you please test out the following:

• Menu app icon > Help > Troubleshooting Information
• Under 'Application Basics' - about 11th in list is Profile Folder - Click on 'Open folder'

A new window opens showing the contents of your 'profile name' folder.

• Exit Thunderbird if running....this is important

• Click on 'calendar-data' folder to see contents.

• click on 'backup' folder.

• Copy local.v22.sqlite from the calendar-data/'backup' folder
• Paste into 'calendar-data' folder, so it is in same place as 'local.sqlite'

• Rename 'local.sqlite' to say 'local.sqlite.bak' - so nothing is lost.
• Rename 'local.v22.sqlite' to say 'local.sqlite' , so the backup has replaced the current.

• restart Thunderbird and report on results.

Whilst the files may seem to be of same size, at this point it is not known if there is some corruption in a file or whether code is causing inability to access and display. Thanks for trying this out as I'm trying to get feedback on whether this method actually works for those who have data stored but seem unable to access it. So your help is much appreciated.

I got to the "click on calendar data file" step but there is no back up file there. I also reverted to v78 to see if that would help and I do not know if that has helped or made the problem worse. Under v78 I can at least get my calendar to work but all old data is still not accessible. I have tried to get the info back by doing a back up and restore but no luck. Should I have left it in v91 for your fix to work?

Charles Petersen

I found the calendar-data folder, and I restored all the backups, one by one. None of them were recent enough to contain my latest data. Posting a new event or task doesn't work, either. I can save it, but the next time I start TB, the newly posted event or task is GONE!

I give up! What else can I do?

Located some excellent feedback so try this:

• Menu app icon > Help > Troubleshooting Information
• Under 'Application Basics' - about 11th in list is Profile Folder - Click on 'Open folder'

A new window opens showing the contents of your 'profile name' folder.

• Exit Thunderbird if running....this is important

• Click on 'calendar-data' folder to see contents.
• Copy local.sqlite file and put copy onto desktop.
• In calendar-data folder - Rename 'local.sqlite' to 'local.sqlite.bak' - but if you already have this that's ok - just delete the 'local.sqlite' file.

Download install addon - Firefox sqlite DB manager add-on into Firefox browser.

• https://addons.mozilla.org/en-GB/firefox/addon/sqlite-manager-webext/

Start the addon - you should see a new icon on the toolbar near the menu app icon - hover over icon and it will say SQLite Manager - clickon it. Use addon to open the desktop copy of the local.sqlite DB drag the desktop copy of 'local.sqlite' into the opened addon.

run two SQL queries - you type this in the yellow area

Searched for items with null id: SELECT * from cal_events WHERE id IS NULL LIMIT 100

If you find any... So then use the following to deleted it: DELETE FROM cal_events WHERE id IS NULL

Saved the database file, 'Save' located at the bottom - save is usually saved in the 'Downloads' folder.

Access the 'Downloads' folder to locate downloaded saved version of 'local.sqlite'. put the saved 'local.sqlite' back into the 'calendar-data' folder

restart Thunderbird and report on results.

Please note: The calendar data has not been lost - it is just not accessible - my previous comment using sqlite db manager addon to find and fix null entries in local.sqlite file has already worked for several people, so this is a known fix.

I am disappointed in Mozilla Management. I think it is irresponsible, of them, to release a new version of the software, with so many changes in the user interface and so many Bugs. There is no way, to contact them directly, to complain, either!

I tried your solution and apparently did something incorrect as when I tried to move the local.sqlite file back I was told I didn't have permission and could go no further. I ended up having v91 reinstalled and am rebuilding some of my files manually. The solution may work but it did not for me and with the reinstallation I do not know if my files are still there or not. I also tried to get them back by using the Windows 7 Backup and Restore but that didn't appear to do anything either.

re :I tried your solution and apparently did something incorrect as when I tried to move the local.sqlite file back I was told I didn't have permission

After saving in sqlite manager, did it download a copy of 'local.sqlite' to your 'Downloads' folder in your 'User Account' or have you got downloads set up to go somewhere else - where did it download?

I'm asking because you should not have a permissions issue, but sometimes Windows is a pain and I've known people store eml files in a folder in 'My documents' only to discover it was stuck there, but they could move it to the desktop from where they had access again. Your feedback would be helpful.

I do not know if it downloaded or not. While I am relatively familiar with computers and their workings but I know I am over my head when I get into the guts of the software. I simply tried to follow your advice and it did not get my files back. Whether I failed to execute your directions correctly or something I did try to improve my condition caused it to fail I do not know. I did move it to the desktop as directed but I do not know anything more than it did not work and would not let me put it back.

re: I did move it to the desktop as directed Assuming Thunderbird is exited and not running throughout the process. That's correct. Then you would have added that sqlite manager addon to your Firefox browser. Then you would start that addon and drag the file from desktop to drop into the opened sqlite manager in the browser. Then use the info to know what to type into the yellow zone. Then click on SAve which was located at the bottom. This would send a download to your computer. Is there any part of the information above which you feel you did not manage to do?

re : I do not know if it downloaded or not. If you followed instructions then when you clicked on Save the new updated version would get downloaded to the default location that receives all downloaded files. Usually, that is the 'Downloads' folder located in your User Account - same place as Documents, Photos, etc. Have you looked in the 'Downloads' folder ?

re :would not let me put it back. No, you do not put the one on the desktop back. You put a copy onto the Desktop which is the one you have been fixing, so original is still in the profile which makes me wonder if you renamed the original to local.sqlite.bak

I know you have since redone things, but knowing what you did or did not do as the case may be helps me to understand where people could go wrong with the instructions, so I could try to improve them for those who need more help.

Yes I did look in my Downloads Folder and nothing related was there. I doubt if there is anything for me to work with or retrieve anymore as I uninstalled v91 to reinstall v78. I did this because as long as v91 was in every time I exited Thunderbird all information I had input dissapeared again. In desperation after help I hired was ineffective (Geek Squad) I upgraded again to v91. Everything now works but old information still isn't there. I suspect I had something incompatible in my old system and deleting, uninstalling and then reinstalling seems to have cleared it. I have another computer and it also upgraded to v91 but there have been no issues and I can detect no information or data loss. I did have trouble with your instructions as you ran things together in your narrative that were separate lines to be typed and I fumbled with that before I figured out what you meant by looking at previously typed lines. Again your instructions may have been spot on and I may have misinterpreted them or had already messed it up enough that they were no longer effective. If I had gotten that help several days earlier it may have worked out differently. So I will move ahead and rebuild what I can and write off what I cannot.