It doesn't look like there's been an update here lately, but I'm having the same problem. I'm syncing to a 128GB SD card in a Sony Xperia XZ Premium, and it's getting very frustrating. Every time I think the problem is fixed, the next time I want to update my synched files (say, a few weeks after a previous sync), a new device profile gets created (actually 2, one for internal memory and one for the sd card), and even though I immediately reconfigure it to my preferred settings it needs to re-encode absolutely everything (Despite the files already existing). For ~10K tracks that takes about 8 hours via USB.

I am using version 4.1.18.1852 with a Gold license on Windows 10 Pro. As far as I know, no other android app (cleaner etc.) is messing with my files. I gather there is a more recent version available, hopefully that will help, but I'm reluctant to upgrade until the current sync finishes (It's about a third of the way through).

Hi,
Are you using some system cache cleaner as that would cause the settings loss. If yes /exclude MediaMonkey folder from cleaner.

Just chiming in here with 4.1.19.1859 and the latest Android release (as of 11/17/2017). Running Win 10 Pro and syncing to Pixel XL.

Having lots of issues syncing my nested playlsits etc, and one of the biggest issues right now is the device profile keeps getting lost and duplicated to a fresh one.

Hi,
Looks like you already done most tests, There is few things you should try:
1. Create debug log as noted http://www.mediamonkey.com/forum/viewto ... ?f=12&t=69
2. Try WiFi Sync when you are sure no additional tracks should be sent to phone and afterwards if you find something suspicions send us log directly from MMA

With above two test done open new support ticket and send us results. That should give us needed details in determine what is gone wrong.

Hi,
I am currently having a problem where my phone is not being recognized over USB and is given a new sync profile when it is connected to the computer. This does not happen every time the phone is connected, but over time it will repeat and result in 3 or 4 profiles for the same phone. Re-selecting all the previous settings and attempting to autosync causes MM to copy a duplicate of every song to the phone and import all the copies of the songs on the phone as if they were new, unrecognized files.
I have tried changing the USB connection off and back on to MTP mode, connecting the phone before and after unlocking it, restarting both the computer and the phone, and deleting the duplicate profiles under Options > Portable Device Sync (the option to delete the original profile is grayed out).
I would greatly appreciate any help with this issue.

(Info)
The phone is a Samsung Galaxy S8+ running Android 7.0 and MMA 1.3.1.0732.
I am running MMW 4.1.18.1853 on Windows 10 Home; this problem occurred before the recent MMW update as well.
MMW is set to scan music from an iTunes Media > Music folder at startup.
The device profile is set to autosync tracks to and from the device and delete unselected library files, and I deleted the <Track#:2> from the sync mask for Music. I sync only over USB.