[quote user="bfluet"]

Unticking the "Turn off attachment preview by default in the attachment view " setting located in Tools > Options > Incoming mail > Message reader will enable attachment preview by default. 

[/quote]

That feature was ticked before I had the Subject problem.  When Unclicked & Reclicked, the Subject problem continues.  For me to view Alternate message formats, I have to manually toggle the Preview button.

[quote user="bfluet"]

Note that it has recently been discovered that the attachment preview mode is causing some problems.  Some folks have experienced the inability to open attachments with a double click and others are unable to save attachments when preview is on.  These problems do not appear to be widespread and appear to be file specific.  Leaving attachment preview mode off by default and using the Preview button as needed might the the best way to go.

 [/quote]

Would that the Preview button would stay in the 'No preview' mode.  In my setup it did until recently.

Something happened that I can no longer view either of the Plain text and HTML text alternative formats under Attachments.  I noticed under Description that the normal "Mail message body" is missing.

[quote user="KSQR"]

Something happened that I can no longer view either of the Plain text and HTML text alternative formats under Attachments.  I noticed under Description that the normal "Mail message body" is missing.[/quote]

There is no description for an email like that that has a plain and htlml part (multipart/alternative).  What do you see when you click on the 'Message' tab?

When I click the 'Message' tab, the Plain Text part is displayed normally.  If I then hit the 'View' tab, the HTML part is displayed normally.

[quote user="PaulW"][quote user="KSQR"]

Something happened that I can no longer view either of the Plain text and HTML text alternative formats under Attachments.  I noticed under Description that the normal "Mail message body" is missing.[/quote]

There is no description for an email like that that has a plain and htlml part (multipart/alternative).  What do you see when you click on the 'Message' tab?[/quote]

Sounds to me like the preview section below the message part tree is "minimized" so the separator ("splitter") needs to be dragged up again from the bottom.

[quote user="idw"][quote user="PaulW"][quote user="KSQR"]

Something happened that I can no longer view either of the Plain text and HTML text alternative formats under Attachments.  I noticed under Description that the normal "Mail message body" is missing.[/quote]

There is no description for an email like that that has a plain and htlml part (multipart/alternative).  What do you see when you click on the 'Message' tab?[/quote]

Sounds to me like the preview section below the message part tree is "minimized" so the separator ("splitter") needs to be dragged up again from the bottom.

[/quote]

Hitting the 'Attachments' button launches another button bar.  When I click the 'Preview' button, it changes to 'No preview'.  In that mode I can view the Plain text and HTML text alternative formats.  Unable to make the 'No preview' setting stick when I shut down PM and restart.

Unticking the "Turn off attachment preview by default in the attachment view " setting located in Tools > Options > Incoming mail > Message reader will enable attachment preview by default.  

Note that it has recently been discovered that the attachment preview mode is causing some problems.  Some folks have experienced the inability to open attachments with a double click and others are unable to save attachments when preview is on.  These problems do not appear to be widespread and appear to be file specific.  Leaving attachment preview mode off by default and using the Preview button as needed might the the best way to go.