Email clients running on Windows 7 may fail if TLS 1.2 isn’t enabled.  To get this going, add/change the following under:

HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols

Add new key under Protocols: TLS 1.2
Add new key under TLS 1.2: Client

Add new Dword in Client: DisabledByDefault = 0
Add new Dword in Client: Enabled = 1

Reboot the computer for this to take effect.

The typical ports for POP/IMAP email now are:

POP port: 995 SSL
IMAP port: 993 SSL
SMTP port: 587 TLS

On a new Windows 11 build, the OneDrive program/app wouldn’t start.

HKLM\Software\Policies\Microsoft\Windows\OneDrive

Change the key DisableFileSyncNGSC to 0

This error was happening when the preview pane in Windows Explorer was on and a .MSG file was selected. There is no 64-bit handler for .MSG messages in Windows, only 32-bit. So a 64-bit set of handler files needs to be added.

We found this fix at https://www.brandsict.nl/msgpreviewer_en.php:

You need .NET 4.5 or higher. This is native to newer versions of Windows or can be activated via Add/Remove features.

1. Download and run this file: MSgPreviewer64_installer. This will create the folder C:\MSGPreviewer64 and place the files there.
2. Open an elevated command window and navigate to
   C:\Windows\Microsoft.NET\Framework64\v4.0.30319
3. Execute these commands:
   regasm /tlb C:\MSGPreviewer64\SharpShell.dll
   regasm /codebase C:\MSGPreviewer64\msgpreview.dll