On the old PC the Address book is called Comments Subscribers. The Distribution List has the same name and its full name is LIST6F75.PML .

On the old PC, Pegasus is in F:\PMAIL. On the new PC Pegasus is in C:\PMAIL .

On the old PC LIST6F75.PML is in H:\Chris . On the new PC I wish LIST6F75.PML to be in a new folder under C: ... Documents to be called Pegasus data . This folder doesn't exist yet.

At least for now, I do not wish to copy other address books and distribution lists.

Both PCs are running Pegasus 4.73. Pegasus on the old PC is only used for sending emails which are created by software I wrote each week. This will also be the case on the new PC.

Pegasus is not used, nor will be used, for receiving emails. Yes, I am avoiding OAUTH.

Should just be copy the correct PML file that is your distribution list.
Then the correct pair of address book, which are PMR and PM! files.

Example: I have an address book and a distribution list
GCCALL.PML
GCC.PM!
GCC.PMR

Could just copy your files to a machine.

I have the lates 4.81pb3 running, but I am still using the app password, so have not used the Oauth2, so doesn't require you to upgrade, and Oauth2 is only currently for Gmail.

I suggest treating the address book and distribution list as system-wide lists. This will allow you to place them in whatever directory you want. Please refer to page 101 in the Pegasus Mail manual for details.

That manual page says that you must set an environment variable for PMR. An alternative to doing that is to use the -V command line option. Details are in Pegasus Mail Help menu, specifically the "Commandline options" item. Keep in mind that this mechanism was created before the existence of long directory and filenames, and before directory names could contain spaces. I don't know whether putting the path in quotes when using the -V option will work nor do I know whether a long directory name such as "Documents" will work. Some trial and error may be required.

Post back if you have any specific questions you need addressed (other than the long filename/directory name/path issue ).

While my email address is not ... gmail.com, it has taken me automatically to GMail for several years. So I have taken the easy route: avoid OATH. Each week, I use Pegasus to send several emails with attachments. These emails are generated by a PerfectScript macro and are then sent using Pegasus. I use GMail for sending all other emails and receiving all emails. Copies of the weekly emails show up in GMail after they are sent from Pegasus. So 4.81 would offer me insufficient advantages.

I am in the process of moving to a new PC running Windows 10.

On my old PC, pconfig.exe shows that my Home mailbox is F:\Pmail\Mail, as is my New mailbox. Strangely, General settings > Home mailbox location shows H:\PMAILCHRIS .

List6f75.pm! and List6f75.pm! are in H:\PmailChris. I understand that these are address book files. But what is the name of the corresponding distribution list?

And on the new PC how do I tell Pegasus where they are after I have copied them from the old PC?

In your original post you said that you wanted the address book and distribution list in "C: ... Documents to be called Pegasus data". You either must set that as the mailbox location and then put the files into a mailbox directory or use the system-wide method I described earlier. I suggest going into the new Pegasus Mail, going to Help > About Pegasus Mail and the clicking the Info button. Copy the entire content of the resulting window and place it into a reply. This will provide us with information about the new installation from which more specific advice may be offered.

AFAIK, a distribution list does not 'correspond' to an address book. They are two different things. As for identifying the filename of a distribution list, in the old Pegasus Mail, press F6 to open the "Addressbooks and distribution lists' window. The Distribution lists tab will show the distribution lists that exists including their filename.