Just noticed there are several identical pairs of folders. No idea how this happened, maybe when the hierarch file was rebuilt? There was one instance of 3 identical folders - when I clicked on one of them, Peg crashed and deleted all of them. So now I'm afraid to click on any of these. Wondering where to go from here, with the whole folder situation seeming to be such a mess.

Attempting to move a message from New Mail to another folder, nothing happens. When I open the folder list, the target folder is gone and there's a new unnamed folder at the top. When I attempt to open that folder, get message that it must be reindexed. But before I can do anything, Peg shuts down. When I reopen Peg and attempt to reindex the folder, get message: "Unable to rebuild folder, failure opening or reading from master file." After closing and reopening Peg a couple more times, the original target folder is back in place, everything seems normal. This has happened a couple times over the past month, never happened before. Is there something I should be doing to avoid this happening again? Thanks!  ...Steve

My suspicion is that something is interfering with the ability of Pegasus Mail to modify its files.  Any changes to your AV product?  Are Pegasus Mail files excluded from active scanning?

Using Windows Defender for virus and spyware (been using this for years with no Pegasus problems). Is there some change I should make in its settings?

Exclude \PMAIL and all subdirectories from active scanning.  I don't know how Windows Defender differs from Microsoft Security Essentials of Win7 but with MSE there is not an option to disable \PMAIL solely for active scanning.  The only option is to exclude it from scanning, period.  Being able to include the files in scheduled and on-demand scans would be my preference since those would be run when Pegasus Mail is not in use.  Dig into the Windows Defender settings and see what your exclude options are. 

Thanks Brian. I've excluded Peg's program and data files. Doesn't seem to be any option to exclude only from active scanning. Any idea why this problem would appear now, after all this time with no issues? Why does scanning affect Peg and not other programs?

I can't answer the "why" part with specifics.  I just know that Pegasus Mail does a good bit of internal maintenance at both start up and shut down and the fact the scanning by an AV product can interfere with its reading and updating of files.  It would suspect that it is also a timing thing.  Maybe 99.5% of the time files are processed so quickly that there isn't any interference but a rare occasion where the AV product has ahold of a file that Pegasus is trying to work with causes a problem.

Also, the fact that your problem is sporadic makes me think that there is some sort of external interference on the normal operation of Pegasus Mail.

The problem just occurred again, so it seems Windows Defender was not the cause? It's a pretty scary problem, having folders with several thousand messages disappear and reappear for no apparent reason. Also having problems saving copies of sent messages - get error message that copy couldn't be made, then it works ok the second time I try.

Have any of the files associated with the folders that go missing hit the 2GB size limit?

No, not even close. I routinely delete attachments and HTML on saved messages, saving only plain text.

If I were you I would now rebuild HIERARCH.PM

Edit:  I fat-fingered something that posted the above before I finished my thought which was that rebuilding HIERARCH can be a daunting task if you have an extensive tray structure because of the loss of that structure but it is a no-brainer if you have a flat structure.   There was a post last week by someone running Win10 who was having problems with HIERARCH but that discussion appears to have died without a response from the OP regarding resolution.  I assume you are running Win10 as well since you mentioned Windows Defender.  That doesn't help solve the problem but may indicate a pattern that might lead to ideas from others.

Yes, I'm using Win 10. Not sure what you mean by tray structure vs flat. I have approx 300 folders under My Mailbox.

Meanwhile, I made some other discoveries in looking at hierarch.pm. There is a 19kb file with current date in the Peg data folder. There is also a 19kb file dated 3-9-13 in that folder, filename hierarch(from sh).pm. There is another file of 253 bytes dated 11-30-13 under c:\Peg\Mail\Admin.

And there is another installation of Peg under Program Files (x86), although I don't see how this would affect anything since Peg is started from the c:\Peg folder.

Go to Help > About Pegasus Mail... and click the "Info" button.  Post the contents of that display in a reply so we can see some of the configuration of the running instance.  That will help us figure out what the next step needs to be.

Pegasus Mail for Microsoft Windows
Copyright (C) 1992-2014, David Harris, all rights reserved
Electronic mail to support@pmail.gen.nz.

WinPMail version: Version 4.70 (Win32), Feb 27 2014, build ID 546
Language resources: Standard UK English resource set
Extension Manager version: 1.14
Operating mode: Standalone
User name and ID: Single-user mode, 0
Windows version: 6.2
Windows flag word: 0
WINPMAIL.EXE directory: C:\Pegasus\Programs
Home mailbox location: C:\DATA\PEGASUS
New mailbox location: C:\DATA\PEGASUS
TMP environment variable: C:\Users\SGH\AppData\Local\Temp
TEMP environment variable: C:\Users\SGH\AppData\Local\Temp
LAN-based SMTP support: N, N, N
NetWare MHS support: N, N, N
Built-in TCP/IP support: Enabled
  - WINSOCK version: WinSock 2.0
  - WINSOCK path: WSOCK32.DLL
Commandline: -A
Active -Z options: 32768
PMR variable: (None)
PML variable: (None)
MAI variable: (None)
NB variable: (None)
Autofiltering folders: 0 (0 active, 0 inactive)
Last new mail count: 48
Message size soft limit: 0 bytes
Message size hard limit: 0 bytes
Attachment size soft limit: 0 bytes
Attachment size hard limit: 0 bytes

I rebuilt hierarch.pm (renamed to .bak and restarted Peg). At first glance the folder structure looks the same, except for a duplicate Deleted Messages folder (both with same filename). I suppose it's safe to go ahead and delete the duplicate?

(Editing this message to note that the problem just occurred again, using the rebuilt hierarch folder. It took 7 restarts of Peg before the folder reappeared.)

[quote user="weamish"]  From previous post:  Meanwhile, I made some other discoveries in looking at hierarch.pm.

There is a 19kb file with current date in the Peg data folder. There is

also a 19kb file dated 3-9-13 in that folder, filename hierarch(from

sh).pm. There is another file of 253 bytes dated 11-30-13 under

c:\Peg\Mail\Admin.[/quote]

Looks like sometime in 2013 you moved your mailbox from c:\Peg\Mail\Admin to C:\DATA\PEGASUS.

[quote user="weamish"]I rebuilt hierarch.pm (renamed to .bak and

restarted Peg). At first glance the folder structure looks the same,

except for a duplicate Deleted Messages folder (both with same

filename). I suppose it's safe to go ahead and delete the duplicate?[/quote]

If the hierarch.pm file you attempted to rebuild was not located in C:\DATA\PEGASUS then rebuild that one.

As for the deleted messages folder, do you keep deleted messages until you delete them?  If not, let Pegasus Mail clean up the duplicate folder issues, or at least attempt to.  Go to Tools > Options > General settings > Advanced settings and disable the option "Deleted messages folder persists between sessions".  Restart Pegasus.  If a Deleted messages folder remains, delete it manually.

If you keep deleted messages, create a new folder as a temporary holding place and move all messages to it from the Deleted Messages folder(s).  Now follow the steps above.  The next time you delete a message a new Deleted messages folder will be created.  You can chose whether to move the saved deleted messages back to it and whether to enable the "Deleted messages folder persists between sessions" option.

[quote user="weamish"](Editing

this message to note that the problem just occurred again, using the

rebuilt hierarch folder. It took 7 restarts of Peg before the folder

reappeared.)[/quote]

I am out of ideas at the moment.

Thanks Brian, sure appreciate your efforts. The rebuilt hierarch file was from C:\DATA\PEGASUS. Cleaned up the Deleted Messages folders per your instructions, looks ok now (I do keep messages until manually deleted). Guess I don't have any tray issues, since the folder list looks identical. Just wish I could figure out what's causing these issues - now I'm afraid to move messages anywhere.

Noticed over the past few days that I'm randomly losing focus in apps. Wonder if this might have something to do with Peg's problems. Figuring out what's causing this could be a nightmare.

Is your Win10 an upgrade done on a Win7 machine that had Pegasus Mail already installed?  I ask because an unknown to me is whether a clean install of Pegasus Mail on Win10 makes any difference compared to it existing through an upgrade.  Knowing whether a problematic Pegasus Mail on Win10 is a clean install or lived through an OS upgrade may prove enlightening.

Also, one other known issue with folder name display occurs when two folders have identical internal ID's.  This is difficult to do but can happen as the result of someone copying a folder file pair (.PMM/.PMI) to another location for archiving purposes then needing access those messages so copying the files back or adding the archive location as an added mailbox.  With that in mind, if the folder name display problem is recurring with the same folder I suggest creating a new one, copying the messages from the bad one to the new one, then deleting the bad one.

I hope you are routinely backing up so you can recover messages should anything catastrophic happen.

The Win 10 installation was an upgrade in place over Win 8.1 (with Peg already installed). The problems have occurred with several different folders, but I'll try deleting and replacing to see if that helps. I run a realtime cloud backup, so should be ok if everything goes south (although of course I could be backing up files that are already corrupted, guess we'll see)