[Chen]

While starting MSP, I get a pop up message "unable to load file: /".

If I click OK, the pop up will be gone until I close MSP and start it again. 
I would like to get rid of this pop-up.   
What file does MSP try to load immediately after launch?

This is on Android 7.1.2.

[Zubersoft]

That seems to indicate you are loading MobileSheetsPro by tapping on a file using another app and it can't load that file. Is that the case? The weird part is that it says the file name is just "/", which doesn't make sense. Had you previously loaded a file that way into the app, then switched to another app, then reloaded MobileSheetsPro by tapping on the icon without closing the previous instance?

[Chen]

Thanks for the quick reply.
This might well be what happened - i imported some attachments from the GMail app. This leads to an message that the running instance needs to be closed for security reasons. Pressed OK, no harm in restarting MSP...
One of the imports was a little weird, as i could not find the imported song afterwards in the song list. I thought i inadvertendly pressed cancel instead of OK, so i just retried the import. This time MSP alerted that the file was already there. I choose "replace" (or similar, i do not remember the exact phrase) and now then the song _was_ in the list. Probably around that time i started to get the "unable to load file: /" message.

After rebooting the device, the message seems to be gone. (i should have tried that first, sorry...!)