You did not say whether you had followed the instructions and compacted the folder? Deleted emails are 'marked as deleted' and from your point of view they move out of folder into Trash, but in reality they are still there hidden from view so the folder may be larger than you think. Compacting removes all marked as deleted emails, so freeing up space and helping to maintain a healthy thunderbird.

To compact all folders: File > Compact folders To compact a selected folder: Right click on folder and select 'compact'

Are you talking about a pop or imap mail account ? what version of Thunderbird are you using?

I notice you say you have 'Trash' folder. Current Thunderbird uses 'Deleted' as the folder name, but if you are using an old version or an IMAP mail account, it may say 'Trash'

Did this message refer to the server Inbox? How many emails do you have in your webmail account which you would access via a browser?

I have nothing saved and trash empties on exit. Folders compacted but I still keep getting the same message. Inbox is full.

My account is Pop3 Thunderbird version 31.1.2

I have a TRASH folder. NOT a DELETE.

Again this is the ONLY error message. The FULL error message:

The folder Inbox is full, and can't hold any more messages. To make room for more messages, delete any old or unwanted mail and compact the folder.

As you have a Pop mail account are you removing copies off the server?

There are various ways to get access to Account Settings

Tools > Account Settings > Server Settings for the mail account or Menu icon > Options > Account Settings > Server Settings for the mail account or right click on mail account name in folder Pane and select 'Settings' and then Server Settings for the mail account

Have you selected to 'leave messages on server' ? If yes, Have you selected 'for at most eg: 30 days' so that recent mail is only kept and older mail is deleted ? Have you selected 'Until I delete them', to remove deleted items of server?

or do you just keep everything on the server because if you do this then you will need to manually access your webmail account and remove old mail so that you do not reach a quota. Logon to your webmail account and see how many emails are on the server. Did webmail account have loads of emails or was it empty ?

Do you only have one pop mail account in the Profile? Are emails actually being downloaded or not?

Also check the Local Folders Inbox as the Alert message does not state which inbox. do you have emails in Local Folders Inbox? Please compact Local Folders Inbox.

Check Profile folders: Make hidden files and folders visible:

• http://kb.mozillazine.org/Show_hidden_files_and_folders

Help > Troubleshooting Information click on 'show folders' a new window opens show

close Thunderbird

click on 'Mail' folder click on 'pop mail account name'

check actual size of Inbox file and also the Inbox.msf file What does it say?

right click on Inbox file (not Inbox.msf) and select 'Properties' under 'General' tab at the bottom see 'Attributes' Is the 'read only' check box selected ? It should not be selected, so uncheck it if selected, then click on OK

Then look in the Local Folders account and perform the same check. What size does it say for the Inbox? Confirm Inbox is not read only.

This is an example image off Profile folder pop mail account. You can see that my Inbox has a size of 3,514 KB what does yours say and also the Local Fodlers Inbox?

Messages are left on server for 1 day at most.

I have Win 7

I cannot fin the location where email is saved. When looking at Users there is no .default or mail folder.

re :I cannot fin the location where email is saved. When looking at Users there is no .default or mail folder.

That's because there isn't a Mail folder in Users.

You have not followed the instructions which will open the actual Profile folder stored here: C:\Users\Windows user name\AppData\Roaming\Thunderbird\Profiles\Profile name\

Did you make hidden files and folders visible? If no then do this. Appdata files are hidden by default. To show hidden folders, open a Windows Explorer window and choose : "Organize → Folder and Search Options → Folder Options → View (tab) → Show hidden files and folders".

Then in Thunderbird Help > Troubleshooting Information or Menu icon > Help > Troublshooting Information click on 'show folders' button see first image below:

It will open a file that looks like the second image below

close Thunderbird click on 'Mail' folder click on 'pop mail account name' you will see something like the third image below

All trash files have 0 kb

I have found some old pop3 email accounts I no longer use.

Can these be safely deleted?

You need to check the Inbox files as the error message is referring to the Inbox and not the Trash.

check actual size of Inbox file and also the Inbox.msf file What does it say?

right click on Inbox file (not Inbox.msf) and select 'Properties' under 'General' tab at the bottom see 'Attributes' Is the 'read only' check box selected ? It should not be selected, so uncheck it if selected, then click on OK

Then look in the Local Folders account and perform the same check. What size does it say for the Inbox? Confirm Inbox is not read only.

re: I have found some old pop3 email accounts I no longer use.

If these pop mail accounts have been removed/deleted from your Account Settings and you do not see them in your Folder Pane, then you can delete them from the Mail folder in your Profile folder.

Inbox1130 kb inbox.msf 0

read-only: Not checked

no inbox in Local just the following

msg filter rules 1 kb trash 0 kb trash.msf 3 kb unsent messages 0 kb unsent message.msf 3 kb

other email on account inbox 959 kb inbox.msf 0 kb

inbox 245 kb inbox.msf 5 kb

these two emails do not have anything in the inbox. Trash is emptied upon exit for all emails. Sent emails are emptied once a week.