re :I have a strange black square that appears when replying to emails. It can be moved with the cursor but won't disappear.

Post an image showing the issue because it does sound unusual.

re :In the Deleted folder, when I empty it, either using 'Empty Deleted' or manually be selecting all the messages and using the delete key, The number of messages drops to zero but the disc space is still occupied. This is in contrast to the junk folder where the operation works as expected.

On pop account and 'Local Folders' account..I get the exact opposite :) Empty Junk removes the emails, but folder has not been compacted so therefore the Size of folder will remain until Junk/Spam gets compacted. Empty Deleted removes emails and does not show size.

However, I also run a beta version of Thunderbird and Pop accounts in release version are set up as Imap accounts in this beta version. In Imap accounts : Empty Junk removes the emails, so count is not displayed but size remains, but only until I select another folder, then size is removed - so obviously a synchronsing delay. Empty Deleted removes emails, so count is not displayed but size remains, but only until I select another folder, then size is removed - so obviously a synchronsing delay.

So, in Imap accounts, I discover, the size is reduced but not until I select another folder.

But 'Local Folders' which also has a deferred pop account using it - That is the same as the release version : Empty Junk removes the emails, but folder has not been compacted so therefore the Size of folder will remain until Junk/Spam gets compacted. Empty Deleted removes emails and does not show size.

So, it seems you should get a different result depending upon whether imap or pop or Local Folders. You may also find certain servers can auto delete emails off the server if they are in the trash. Gmail do it every 30 days, but some do it every 7 days and I've even come across some that do it in less time. It means, you may have emails in Trash, you select Trash to check on them only to discover this is an imap account and the Trash has now synchronised with server and suddenly a load of emails disappear before your eyes. Imap folders can only display whatever is displayed on server.

Examples: Yahoo server does this:

• Trash deletion frequency - Trash is deleted after 7 days.
• Spam deletion frequency - Spam is deleted after 30 days.

Xfinity server does this:

• Flagged spam: deleted after seven days
• Trash: deleted after 14 days

The black square appears as soon as I start typing but, if I move the cursor, it disappears until typing recommences. I've had to send you a photo because screen shots change the conditions. I hope this is of use.

Thanks for your help.

Regards, Paul

When I'm using eg: mouse to move about in the 'Reply' box my text cursor looks like a capital i with line across top and bottom. The mouse pointer icon should change to that icon when hovering in a text zone. I think it's called a I-Beam cursor. Do you see that text capital i/I-Beam type of icon ? Do you get the black box as a substitute for a text mouse cursor ?

The flashing text cursor itself is a straight line at end of text as per your image. So it's nothing to do with that.

I've been checking out various things to find out what's going on. I've found a similar cases : Some people using Windows OS discovered this was linked to their mouse pointer which normally looks like an arrow, but suddenly had a small black square with it - changing mouse pointer arrow cursor color to black instead of white solved their issue. Several people had a similar issue in Adobe a few years ago, but I think that issue was specific to an adobe update.

Do you get the same issue if typing in another program like Notepad etc? Or if typing in this forum question reply box - but you do need to make sure the mouse pointer is in the same text box area ?

Hi, Thanks for your feedback. Unfortunately, the black square only manifest itself in Thunderbird and doesn't appear to be related to the mouse pointer. So, it's still a great puzzle. I did think of uninstalling and re-installing Thunderbird. Do you think that would solve the problem (it also has a habit of corrupting files/losing which means that I have to re-build the database). Any more wisdom would be appreciated. Regards, Paul