FYI, I just experienced the same bug with the latest version of MMA. I have a Samsung Galaxy S3, 16GB internal and 64GB external card (with 33GB used).

Rebooted my phone to try and get rid of a constant spinner. The spinner disappeared, but so did all music (not the playlists). I'm guessing that the spinner was now quick to disappear because there was no music on my phone.

No, I'm not going to re-run the test as it takes a good hour to get all my music back on the phone.

CP

My GS3 has a 16GB internal card (which i dont use for music) and a 64GB external card (which is 90% filled with music).
The card size cant be the problem since it is working flawlessly with everything else but MMA. I haven't had a single problem with iSyncr or PlayerPro.

It was a real kick in the pants to have MMA sync for hours and hours over WiFi only to have everything wiped out in a hearbeat. I really need some sort of confirmation from the devs that this thing is fixed before I even consider going near MMA again ! No app should be able to wipe you out like that.

I know this wont help but ..

I am using MMA .0095, Samsung SG3 and MM4.1.0.1622

I was interested in this problem ... to see if it happened to me so I tried it. I disconnected my phone from the computer (usb) then stopped MMA then powered down. Turned back on after a few minutes and started MMA back up. All songs were there ... in fact they were SO there that they were duplicated (which i will report in a separate thread).

So, although I can't duplicate your issue .. i did find something else <G>

Let me know if there is something else I can try to duplicate

they just released another update for mma last night. maybe it is fixed now?
some times doing new program version updates rusty is too busy to send out email replys instantly maybe one of the others have fixed it in this update and did not think to send you any email.?

its gotten a little fast in there now days with mmw and mma and now win8 all needing fixed updates at once i don't think if rusty was an octopus he would be any more relaxed with those 8 arms all going every which way they could at once. He would need 8 more of them i think to slow down and reply to emails.

i had hoped he would get to you fast on it as he does come in the forum and read posts. and the others do also and have read this thread i'm sure if they knew the answer they would have replyed to the thread, but for that they would need more info in the thread like size of sd card there were some reports of samsung only seeing 32gb cards and not anything larger. so if you have that huge of a card maybe that is the cause of the error? i know galaxy 1 came with a 16gb card. or was that 2 that came with that one? so it seems that samsung knows about that limit, and in another forum some have mentioned issues with samsung and some rumors that they are wanting their own phone software like windows did. which might make it even harder to get mma to work on the phones.
i know its not much help to you but i'm just telling you info i've found around the web.

itunes is really well it's umm? well I think it could be,,, ah the heck with it.

thats why i got android.

I haven't heard a thing back from you guys about this bug. This is a major problem (an app that completely wipes all songs off your SD card). I have been a paying MMW customer for years and was really excited that Mediamonkey was finally getting on board with mobile syncing, but until this problem is fixed the program is completely unusable (much less a decent competitor in the market) !

In the meantime I have had to switch to using iTunes with iSyncr and PlayerPro (this combination is working very smoothly by the way). Its really sad that after all these years of telling everyone that they were idiots for using iTunes I had to come crawling back.

FIX THIS PROBLEM PLEASE !!! I AM USING ITUNES FOR GODS SAKE !!!

Good hope rusty finds the answer fast for you.

Just did the following:

1) Wipe all data (on MMA and MMW)
2) Install MMA
3) Sync 8 songs to phone via WiFi (they all play fine)
4) Send log
5) Restart phone
6) Start up MMA (all songs are gone)
7) Send log

Going to send a PM to Rusty right now.

So the mma is on phone and music is on phone, do these steps.
1. Go to options of mma and on bottom of page press the debug logs to send in a copy of while everything is on phone.
2. Turn phone off and restart it.
3. Now open mma and go to options the debug logs and send in another one to show what happens when all songs are gone.

And send pm to rusty or jiri and tell them what you sent or when you sent them so they can look for them to check the errors if any.

Galaxy S3 (External Card) / MMA 90 / MMW 1617

I can sync up my phone using either WiFi or USB and everything plays and arranges fine, but when I reboot my phone everything is gone. The app has deleted all the songs I synced and none of them show up in MMA. I checked my card and the entire music folder has been removed from my phone !!!

If MMA is not installed and I put songs on my phone and restart it this does not happen.
If I sync to the internal memory nothing is deleted. This only happens when I have the external card synced.

This is a really big problem seeing as I keep all of my music on the external card!