That did it. Thanks much for your help.

As I started up Pegasus Mail, it began the startup process, but then froze at the place where it says "Opening New Mail." I tried updating to the latest version and it still does the same thing. It is just frozen there. After a time, a window will come saying the program is not responding and give me a choice of waiting or shutting it down. I have also shut it down using the Windows 10 Task Manager. When I try to restart the program, I get the "Mailbox is Locked" window. Clicking on "Continue" brings me to the same problem. Any suggestions?

[quote user="fdavis"]As I started up Pegasus Mail, it began the startup process, but then froze at the place where it says "Opening New Mail." I tried updating to the latest version and it still does the same thing. It is just frozen there. After a time, a window will come saying the program is not responding and give me a choice of waiting or shutting it down. I have also shut it down using the Windows 10 Task Manager. When I try to restart the program, I get the "Mailbox is Locked" window. Clicking on "Continue" brings me to the same problem. Any suggestions?[/quote]

To get rid of getting the "Mailbox is Locked" window when restarting the program is to delete the C:\PMAIL\MAIL\MAILBOXP.LCK file.  One way is to use a batch file containing:

if exist C:\PMAIL\MAIL\MAILBOXP.LCK del /q C:\PMAIL\MAIL\MAILBOXP.LCK

 Have no idea about fixing the program freezing on startup.

KSQR

Thanks for those thoughts. I am not familiar with using batch files, though. Do I just go into explorer and delete that file? Is there really any value in eliminating the "Mailbox is Locked" window? If I understand you correctly, this will not solve the bigger problem of the program not actually working. Am I right about that?

[quote user="fdavis"]

Thanks for those thoughts. I am not familiar with using batch files, though. Do I just go into explorer and delete that file?

[/quote]

That is another way.  

 [quote user="fdavis"]

Is there really any value in eliminating the "Mailbox is Locked" window? If I understand you correctly, this will not solve the bigger problem of the program not actually working. Am I right about that?

[/quote]

The  MAILBOXP.LCK file is created when Pegasus Mail is launched to keep you from launching it a second time. Perhaps deleting the .LCK file will solve your problem.

KSQR

Will this have an effect on what goes on in the future? For that file to even exist there must be a reason for it? Is there a problem with Pegasus launching a second time? I feel hesitant to delete things where I don't know the ultimate effect.

 If I uninstall the program and reinstall might that be a solution? If I did something like that, would I loose previous data?

Don't worry about manually manipulating the .LCK file.  Hitting the "continue" option at the mailbox locked prompt will clear it. 

The problem with the startup hang when opening new mail is a bad new message file.  Use a file explorer to navigate to your new mail directory (default is C:\PMAIL\MAIL\ADMIN) then look for any zero byte .CNM files and delete them.  If you don't find any, move all of the .CNM files newer than the last time Pegasus Mail started out to a temporary location.  Pegasus Mail should now start up.  Shut it down then move a few of the .CNM files back keeping track of which ones you moved, test.  Repeat until Pegasus Mail hangs.  You then know it is a file in that batch that is the problem.  Narrow it down from there.  Note that .CNM files are plain text files so can be viewed with a text editor.

BTW, a reinstall rarely solves a problem.  Most problems are associated with a configuration file or a mail file, neither of which a reinstall touches.

That did it. Thanks much for your help.