Hi, Oscar. The button always stays greyed out until you click *somewhere* on the dialog box; after the briefest pause, suddenly the 'OK' button is enabled. This confused me a lot at first. I still don't know why it works this way, but it is no longer a problem for me, at least.

If this is NOT the problem in your situation, please reply, and perhaps offer additional specific details. Perhaps I or someone else can still help then. For instance, are you actively selecting the correct viewer (which would require clicking somewhere on the box, or interacting with it via the keyboard), or are you actually saying "even though the correct viewer is already selected when the "open attachment" dialog appears?

Even though you can't open the attachments directly from Thunderbird for whatever reason, you should be able to right-click on them and 'Save as...' to store a copy on your computer which you could then open normally. That would serve as a workaround, if not a permanent solution. You'd be able to open them.

Have a blessed day, Oscar. I hope we can help you. This would be such a basic and annoying problem.

CV:

Thanks for the prompt reply. Appreciated!

1. I find no functionality like the "click *somewhere* you described. I clicked 10 times inside the dialog box and the OK button still stays grayed out. 2. The right click and save works for PDFs but not for Excel files. With the Excel file both "save as" and "open" just pop up the TB dialog box and again the OK button never becomes enabled.

Need more help.

Thanks.

Oscar

What do have in this location - post an image. Menu app icon > Options > Options > Attachments > 'Incoming' tab

Hi, Oscar; you're welcome.

Re: Click *somewhere* on the dialog box The asterisks are only for emphasis, in place of underline formatting. It was not specifying any particular thing. :-) ... In any case, that did not work for your case here.

I'm glad you have a temp workaround for PDF's, but I am stumped as to why *any* file types are treated differently than others. I expected that right-clicking any attachment and clicking on 'Save as...' would bring up the operating system's 'Save as...' dialog box to prompt you for a location and filename for the saved file -- no matter what kind of file you are dealing with.

In the case of Excel files ... and this question is so basic that I know what it sounds like ... but do you have a program that will open them installed on the computer on which you are working when you have these problems? Assuming yes, have you tried clicking on the drop-down box that lets you choose the program you want to use to open the Excel file, and choosing another instead -- just to see what happens, regardless of whether another program can open the file usably or not? Even try choosing another program and then choosing Excel (or whatever program you use) again. I am not guaranteeing useful results from this, and it shouldn't be necessary; I am just trying to check any little thing that occurs to me while perhaps others can help you find and fix the underlying problem.

I wish I could help further. I'll still see notifications about this question, though, in case I can again. Good luck!

Menu app icon > Options > Options > Attachments > 'Incoming' tab

Is the .csv excel document set up to use: Use TWINUI (default) ?

If no then change to that setting and try opening.

Good call, Toad-Hall. Oscar, this is mainly just extra clarification, expanding on what they just wrote, for future readers if nothing else -- so if you don't need it yourself, no harm done.  :-)

Just to help *make sure* you understand what Toad-Hall is asking for right away, what they want to see is the list of actions that your installation of Thunderbird takes when you try to act on each type of file. (I will include a picture of that screen below.) Those actions include "Always ask [the user what to do]", using a specific program to open a given file type, and a couple other choices. To show them all will require multiple screen-shots, probably. Of course, you say that PDFs and Excel files are your biggest concerns, so be sure to show us at least what your Thunderbird is set to do with those.

He says correctly to go through Menu app icon (the "hamburger menu" button that shows three short horizontal lines stacked vertically) > Options > Options > Attachments > 'Incoming' tab. For people who have the menu toolbar shown, one can also use the Tool menu to get to the same screen: Tools > Options > Attachments > 'Incoming' tab.

[Just to see what would happen, I deleted the action associated with the PDF file type in my Thunderbird 68.0.7, and then I clicked on a PDF attached to a letter. PDF is no longer in that list of file types on my computer (and I don't immediately see a way to put it back). Even then, Thunderbird still shows me the dialog that asks me whether to open the PDF file with a specific program or save the file (or cancel). (That seems to be a default action for unspecified file types, then.)]

Hopefully something there will be useful :-) .

Thanks for all the replies. Much appreciated.

All is fine now (including an audio playback issue), seems it may all have been a Win 10 update issue.

Thanks again and God bless!

Oscar