Caja flags MS Power Point Presentation files (ppt) as "unknown type".

[thealamenthe]

I have been using Linux Mint Mate on and off for quite a long time and recently did a fresh install of LM 20 (Ulyssa). I encountered a problem whereas Caja flags MS Power Point Presentation files (ppt) as "unknown type". The problem is that the error shows up only when the folder is a Network folder (resides on a NAS). When clicking on the file to open with LibreOffice Impress a dialogue window pops-up "Could not display smb://.....ppt, The file is an unknown type". I am able to click on "Select Application" and open the file. The problem does not manifest itself in local folders as Caja flags ppt files correctly as Microsoft PowerPoint Presentation.

Steps taken to isolate/resolve the problem
1) Did a complete removal of Caja and re-installed. Problem persists.
2) Booted a live Linux Mint Mate and connected to the NAS folder. All ppt files were flagged correctly as Microsoft PowerPoint Presentation (application/vnd.ms-powerpoint). Able to open the files.
3) Installed Dolphin File Manager. Files in the NAS folder are flagged correctly as Microsoft PowerPoint Presentation (application/vnd.ms-powerpoint). Able to open files.

It appears that the problem is isolated to a Caja issue and only relating to the network folder containing ppt files. BTW, I have another Network folder on the same NAS that contains jpegs and do not have any problem opening these files.

Any insight into this problem would be greatly appreciated.
Thanks

[Reddog1]

I don't use Mate, but I imagine you have, somewhere in Settings there, a Mime Type Editor. Go there and look for Application/vnd.ms-powerpoint. The listed app should be LibreOffice Impress as Default. Below will be a list of powerpoint applications. Click on them one-by-one and choose LibreOffice Impress as the app to open each one. There will be a change from Default to User Set. Then test to see if that helped.

[thealamenthe]

Thank your for your input. I did look at the mime list in .local/share/applications/mimeapps.list and it does associate power point presentations to LibreOffice Impress. The fact that I am able to open files from the local folders would indicate that this is not a mime issue. The problem manifests itself if the ppt file resides on a network folder (NAS). I also don't believe this is a permission issue as I was able to open the files using Dolphin FM. I've done a work around by adding a launch item in the Caja context menu.