Thunderbird calendar mint 21

I share the calendar via an *.ics file stored on Dropbox this worked fine for years. Now when a new item is added to the calendar is is not synced to other users.

Any suggestions please.

Hi Tramlink,

Do you mean the .ics file isn’t sync’d to other user’s dropbox accounts, or that it is sync’d but isn’t being imported into their calendars?

I’m sort of guessing it’s the former (?) in which case have you had a look at this?

If not, can you describe specifically what you were doing in Thunderbird that’s no longer working and how long it’s been stopped for?

All the computers use the same Droopbox the updated (i.e. a new appointment) .ics file is not being imported into their calenders,

Interesting, I’ve not used Dropbox / Thunderbird … so was Thunderbird previously just seeing the file and automatically importing it? (what happens when you try to import it manually?)

Hi guys
I’ve been watching this thread with some interest because I do a very similar thing but in a different way, I have a synched folder on each machine using Syncthing and place the .thunderbird file in that folder and use a symlink from ~/.thunderbird to ~/synched folder/.thunderbird, that means any PC/Laptop running thunderbird & sharing that folder will automatically sync everything ie email, address book & calendar.

I’m not saying this is a better way to do it and even if it was it may not be a suitable solution for your specific purposes but it does work (at least for me) although I see no reason it why it wouldn’t work with Dropbox but I’d be reluctant to use Dropbox for that purpose for security reasons

Good luck

The .ics file on Dropbox is seen as a locale folder. Each computer sees the file on Dropbox as a local folder and every X mins it checks for changes and imports the changes.

This sounds interesting but sounds like it would only work for computers connected to the same LAN. Using Dropbox allows access from any where in the world so that you can see changes made by whatever computer has the right to change entries in the calendar.

Ok, so it sounds like somewhere down the line Thunderbird / Dropbox will be using the inotify subsystem to keep track file changes, as it seems to be failing to spot changes, I’m wondering whether this might be the issue.

Can you check in syslog to see if you’re getting any inotify resource warnings?

grep inotify /var/log/syslog

If, with Thunderbird and Dropbox running you try this;

for foo in /proc/*/fd/*; do readlink -f $foo; done | grep inotify | sort | uniq -c | sort -nr

If you add up the numbers in the resulting output, that should be the number of inotify_user_instances in use. If you then cross-reference this with the number configured for your system;

$ sysctl fs.inotify
fs.inotify.max_queued_events = 16384
fs.inotify.max_user_instances = 128
fs.inotify.max_user_watches = 4194304

If the number of instances in use is anywhere near max_user_instances it might be worth upping the limit;

$ sudo sysctl -w fs.inotify.max_user_instances=256
fs.inotify.max_user_instances = 256

Alternatively you could check the number of user_watches;

$ lsof | grep inotify | wc -l

And compare this to max_user_watches, it sounds like Dropbox can use quite a few depending on the number of files and folders in the monitored directory. Is it possible that the folder in question has recently had a lot of files added to it?

This does seem to be an issue other that has affected other Dropbox users, although I would expect something in syslog to indicate an isue.

This sounds interesting but sounds like it would only work for computers connected to the same LAN. Using Dropbox allows access from any where in the world so that you can see changes made by whatever computer has the right to change entries in the calendar.

Syncthing can work remotely, I used it to share files between my office PC and Home PC before I retired, it could offer more flexibility in terms of what files are shared between each machine but the downside is it can be challenging to set up and it may not be quite a reliable as Dropbox


Hi there is no syslog - data.

  1 /proc/2635/fd/anon_inode:inotify
  1 /proc/2596/fd/anon_inode:inotify
  1 /proc/2579/fd/anon_inode:inotify
  1 /proc/2505/fd/anon_inode:inotify
  1 /proc/2460/fd/anon_inode:inotify
  1 /proc/2448/fd/anon_inode:inotify
  1 /proc/2418/fd/anon_inode:inotify
  1 /proc/2399/fd/anon_inode:inotify
  1 /proc/2397/fd/anon_inode:inotify
  1 /proc/2351/fd/anon_inode:inotify
  1 /proc/2332/fd/anon_inode:inotify
  1 /proc/2323/fd/anon_inode:inotify
  1 /proc/2313/fd/anon_inode:inotify
  1 /proc/2306/fd/anon_inode:inotify
  1 /proc/2293/fd/anon_inode:inotify
  1 /proc/2288/fd/anon_inode:inotify
  1 /proc/2269/fd/anon_inode:inotify
  1 /proc/2265/fd/anon_inode:inotify
  1 /proc/2251/fd/anon_inode:inotify
  1 /proc/2239/fd/anon_inode:inotify
  1 /proc/2125/fd/anon_inode:inotify
  1 /proc/19954/fd/anon_inode:inotify
  1 /proc/18921/fd/anon_inode:inotify


It would seem that the file on Dropbox online has not been updated since October but the local file is up-to-date.

So are any files in that folder syncing with dropbox online? What does it say the sync status is when you check the desktop menu?

All the other files and folders seem to sync OK, The Icon says all files are up to date.

But as I sad now I check the .ics file has not been up-dated for some months. This would seem to be the reason why the calendars on the other computers are not up-dating.

What happens if you create and share a new .ics file, does that work?

I tried creating a new file and used this to create new calendars on the other computers in the net work.

All had up-to-date calendars however when new information is entered it is not synced to the other computers.

This seems strange as I am using the method described on the Thunderbird Help pages for sharing calendars.

Ok, so does this mean the issue is that dropbox isn’t syncing files between machines, rather than Thunderbird not importing them? If so;

Seems like a lot of similar issues are being blamed on firewalls and anti-virus software …

I do not think this is the problem as files uploaded or changed on Dropbox by any of the computers on the LAN seem to update on all the other computers.

It would seem that the ics file on Dropbox is not being updated or Thunderbird on the other computers is not syncing the changes to the ics file.

Ok, so at this point it’s unclear to me exactly what the situation is. On the one hand you seem to be saying you able to write files to drop-box and they are sync’d with other computers, but on the other, the .ics file isn’t being sync’d. Is it that dropbox seems to have something against this particular file, or is it that changes are not being written into this file in the first place?

If you manually change this file, just something simple like the update time, is this change being sync’d around the network. (you could use “touch (filename)” to change the files update time, then “stat (filename)” on other machines, just to see if the timestamps match?)

If you can narrow it down to a dropbox sync issue, or a Thunderbird .ics file update issue, that will help.

To see if it was a Dropbox or Thunderbird issue I tried using my synced Google Drive and it seems that any changes are not being sent from Thunderbird calendar to the ics file.
So it seems to be a TB issue. I also reinstalled version 91 on my computers yet the issue continued the ics file is not being updated.

Ok, so I’m not a Thunderbird user so I’m feeling my way in the dark a little, but as I understand it, when you create a calendar, you can specify it’s storage as an .ics file. So I’m assuming this is what you’ve done?

In this vein, you can have multiple calendars, all of which can have different storage backends, whether .ics files or other types of storage.

When you create these new events that are not appearing in your .ics file, is it possible that they are being created in “other” calendars, i.e. not in the calendar backed by the .ics file you are looking at?

At last after a lot of searching on the web it seems that recent program updates means that the program is no longer talking to ics files.
ics files can still be read to export or import information but not for calendar syncing.

Luckley we have a a Google account in the company name and can use this calendar within Thunderbird.

So I am closing this post, it’s a pity users were not informed about this change when the program was updated.

Thanks for all the help.