MARQ Expedition gremlins over last two days

Painful though it is, my usual recourse in such situations with Garmin GPS watches (since the Fenix 3) is a Master Reset of Settings and Data then set the watch up again from scratch.  I've found if I try to restore any settings from a backup of settings files, they often bring bugs back with them.  Also worth checking that you are on the latest device software using Garmin Express (don't assume GCM has delivered any updates); I think the current production version is 3.10 and there is a beta thread on here with a link to grab 3.31 beta (the assumption that beta software is not 'stable' is generally not the case, the betas generally run very well and contain some important fixes).

Thank you Crispin for your reply.  Have tried a master reset once of settings and data (into system/reset/delete data and reset settings) and still have the same issues.  Have also now noticed that direct syncing of data does not work and reports an error of 0300 (although the watch does successful connect to the network initially).  Have tried this on two different networks - one password protected and one not and both show as linked in GC.  Further communication issues it would appear! 

Devon Tosh, are you removing the Wi-Fi networks from your Expedition and re-adding them?

After many hours of head scratching, I now seem to have a solution - basically by removing a number of maps that I had download from the purchases section in the Garmin Express App.  I'll go into a longer reply below in that this may help others but in summary I now have BT working for music playback; no issue with distances recording and routes being tracked on maps in activities; no hanging when I finish or discard an activity; GCM is now working as is file transfer over Wifi.  Not sure how all of this is related to I guess a corrupt map file but it seems it was.  

To put this into context: 

I had a number of European TOPO light maps covering many European countries (approximately 10 in total including the UK Topo Light map).  I downloaded the UK light one last weekend all was well - the problems only started after I downloaded all of the other countries in the middle of last week which took multiple downloads as I kept getting server issues and download fails.  Perhaps this corrupted some of the files?

After the suggestion of Crispin above (thank you), last night I backed up my entire Garmin File over to my Mac desktop via AFT and then started removing some of the purchased maps off - only leaving the original ones that came with the watch preloaded.  Once done, the watch started working again without having to do another Master Reset.  

A great relief!  I'll post a screen shot of maps in the purchased section of my GE app once my watch has finished repopulating Basecamp

Only one question from me - my remaining maps are just sat in the main Garmin folder (and seem to work there).  Should they be under a sub folder or does this not matter (i.e. does any app requiring access to a map just look at the Garmin folder or does it look at a sub folder? 

All Garmin devices store the map files in just the Garmin folder.  So those maps are in the correct place. 

On the subject of removing extra maps, you added to your device and that fixed the issues you were experiencing, I am not sure how mapping could affect the device.  Feel free to send me a Private Message with the list of maps you had installed, and I would be happy to download them too and try to reproduce it.

Thank you for your response and I remain a confused as you!  Not sure how map files could cause this much harm.  This is a screen shot of the maps I downloaded

I was unable to connect to my plantronics backbeat fit today.  I didn’t full reset but restarted to no avail.  5+ never has problems.