Problems attaching files to outgoing emails

[newmo]

Hi folks,
My first post here - hoping someone can point me in the right direction!
I have been using Mint and Thunderbird successfully for a number of years now and love Mint. Previously, I've had no problems that I couldn't resolve myself but an issue has arisen which has got me stumped.
In the past, I have regularly attached files to outgoing emails from a usb stick. Following some recent problems with the computer (long story!), I was forced to do a fresh install of Mint and am now running 17.3 KDE 64bit and TB 52.4.0. I now find that, when I select the "Attach" button, the dialogue comes up but I am unable to browse to any files on the computer or usb. The dialogue looks like this:

the locations do not respond to clicking. All I can do is cancel and drag and drop files from Dolphin.
At first, I thought this was a Thunderbird problem but, when I came to upload a file to Dropbox, I found the same problem. Also, I have the same version number of TB running on my windows partition and that will browse and select files to attach fine.
I have looked through all the system settings and TB settings that I can find, and also tried to research on google but only found posts from years ago.
Any of you kind people have any idea what is causing this issue?

[Spearmint2]

what file system is on the USB flashdrive? FAT32, NTFS or an ext type?
You see them using file manager. Can you open the files too?

[newmo]

Hi Spearmint2 and thanks for taking the time to respond,
The usb stick is formatted fat32 but I should have said that this problem is exactly the same when no memory stick is attached i.e. I can't attach files from Documents, Pictures etc. That was one of my first thoughts when I encountered this issue so I tested various configurations, including starting up with no memory stick attached - exactly the same, I'm afraid.

[newmo]

Oh, and as to your last question, yes, I can open all files normally from Dolphin, both from the PC itself and the memory stick. It's only when I try to "send" them somewhere, either as attachments or uploads that I encounter the problem. The dialogue in the image that was in my first post is kind of frozen - it doesn't respond to clicking on any of the locations.
Kind regards
Frank

[Spearmint2]

OK this isn't just the stick then.

Following some recent problems with the computer (long story!), I was forced to do a fresh install of Mint and am now running 17.3 KDE 64bit and TB 52.4.0.

This is the Thunderbird version that installed at the same time with the KDE during the install? Did you check the ISO file's md5sum or sha256sum to see if it matched what it's supposed to, to insure you didn't install from a corrupted download?

on your Menu search type in gtkhash. If there, open it, check the ISO file you used for install. Compare to what it should be.

https://www.howtogeek.com/246332/how-to ... ered-with/

what it should be;

sha256sum

be64bf240a47df03fedca1b8aeb9357896e3dedd55446a0f87eca4f638c9d28c linuxmint-17.3-kde-32bit.iso
aa33bf286e92556163c335b258fe5cbd9f65f4ab8490e277fed94cf20d3920e4 linuxmint-17.3-kde-64bit.iso

md5sum

6a42a8ec6ad050ada8478ba2f0d8586b linuxmint-17.3-kde-32bit.iso
9fae1a87bebe4b57f6a587272f0cee3d linuxmint-17.3-kde-64bit.iso