Brian you are a star! HEIRARCH.pm was read only.

All seems to be working properly now. Thank you very much

I re-organised my mailbox system, creating new mailboxes and folders and moving files. When restarting Pegasus the new ones have disappeared and the old ones I emptied and deleted and returned. Any suggestions?

[quote user="Tony Herrmann"]I re-organised my mailbox system, creating new mailboxes and folders and moving files. When restarting Pegasus the new ones have disappeared and the old ones I emptied and deleted and returned. Any suggestions?[/quote]

Well, since you're talking about files and folders without providing the exact context we've got to know these details here before anything else: What are you talking about, especially if dealing with Windws 10 as I assume you are: Did you do any of this outside of Pegasus Mail, inside it's internal mailbox management system only or both of these and where and how exactly in Windows did you install Pegasus Mail and its mailboxes in the first place? You might want to start with the information provided by the menu entry's Help => About Pegasus Mail => Info screen to learn about your installation paths and possibly share them with us.

Thanks Michael

WINPMAIL.EXE directory: C:\PMAIL\Programs

Home mailbox location: C:\PMAIL\MAIL

New mailbox location: C:\PMAIL\MAIL

TMP environment variable: C:\Users\TONYPC~1\AppData\Local\Temp

TEMP environment variable: C:\Users\TONYPC~1\AppData\Local\Temp 

I have done all changes within Pegasus Mail and yes Windows 10. I had a number of 'loose' message folders under the main My Mailbox. I created new folders inside some existing filing trays and then moved all the Messages into those new folders. On restarting Pegasus, the new folders had disappeared and the old ones were 'still' there with the messages in them as though nothing had changed.

[quote user="Tony Herrmann"]I have done all changes within Pegasus Mail and yes Windows 10. I had a number of 'loose' message folders under the main My Mailbox. I created new folders inside some existing filing trays and then moved all the Messages into those new folders. On restarting Pegasus, the new folders had disappeared and the old ones were 'still' there with the messages in them as though nothing had changed.[/quote]

OK, this indicates that Pegasus Mail wasn't able to save its configuration files to the Windows folder it is supposed to (it should be the New mailbox location. i.e. C:\PMAIL\MAIL in your case. In there should be a file called HIERARCH.PM which is supposed to contain all data concerning your mailbox structure. If this file hasn't been updated during you're most recent Pegasus Mail session (at least after opening and closing Pegasus Mail once) this indicates a file access issue. It even gets updated without changing your mailbox structure at least once during each Pegasus Mail session.

For checking the file's most recent "Modified" time open Pegasus Mail, wait at least for minute and close it, for being sure you might temporarily add a new folder during this time for test purposes. Then locate HIERARCH.PM in C:\PMAIL\MAIL, right click it, select the property entry at the bottom of the context menu and check the "Modified" time stamp. If it doesn't show anything in the time interval Pegasus Mail had just been open you'll know for sure that Pegasus Mail couldn't write to it.

So now for the first try to solve your issue: Go to this website and follow its instructions to turn off Controlled Folder Access, then check again like described above.

Thank you very much for info and suggestions. I will do as you propose and let you know

Ok. So it hasn't been modified for over a year.

So, Windows defender antivirus is turned off.

Avast Business antivirus is turned on.

[quote user="Tony Herrmann"]

Ok. So it hasn't been modified for over a year.

So, Windows defender antivirus is turned off.

Avast Business antivirus is turned on.

[/quote]

Tony, it isn't an AV issue, it's Windows itself which doesn't permit file modifications by "Apps" that aren't explicitely allowed to, and Pegasus Mail cannot currently get this permission since it is an "old style" application. You need to follow the instructions given on the linked website to explicitely disable the Windows 10 Controlled Folder Access feature which isn't controlled by AV applications. It's described under Option 1 on this page.

I can't find a way to get the Controlled Folder Access option to appear.  It seems like as Avast AV is on and Windows Defender AV off, the option is not there

[quote user="Tony Herrmann"]I can't find a way to get the Controlled Folder Access option to appear.  It seems like as Avast AV is on and Windows Defender AV off, the option is not there [/quote]

OK, maybe then you have another issue preventing Pegasus Mail from writing its configuration to its proper files, but I don't have any further ideas other than: Make sure that AVAST doesn't interfere here.

Definitely insure that \Pmail and its subdirectories have been excluded from active scanning by Avast.  It is ok to keep them included in scheduled scans.

If the problem still exists after that then the file properties of the HIERARCH.PM file to make sure is not ReadOnly.  This file stores the folder structure.  It resides in the New Mail directory (C:\PMAIL\MAIL in your case). 

If its not ReadOnly then my concern is some some sort of corruption to HIERARCH.PM that is preventing it from being updated.  It is very easy to create a new HIERARCH.PM but there is a huge GOTCHA for anyone who uses Trays.  A rebuild of HIERARCH.PM flattens the Pegasus Mail folder structure.  All Tray structure is lost.  IIFC, all Tray names are lost as well.

A problem with HIERARCH.PM is relatively easy to test for.  With Pegasus Mail closed, you would rename HIERARCH.PM to something like HIERARCH_PM.SAVED.  You would then start Pegasus Mail.  During startup it will poll each folder file to create a new HIERARCH.PM file.  You would then want to create a Tray structure, one Tray with a couple of folders in it.  Don't get elaborate because this is just to test if the structure sticks.  Close then reopen Pegasus Mail.  If the structure you created sticks then you know that the new HIERARCH.PM file is working as it should and you can rebuild the Tray structure.  If the structure doesn't stick then you know the problem is elsewhere and can restore the renamed HIEARACH.PM file (while Pegasus Mail is closed).