Yesterday after recent DJI Go 4 update I flew two batteries on my Mavic Pro doing long range flight.  On the thrid battery and while some distance from my controller, my DJI Go 4 app crashed giving me a "Lost Connection Error" and complete loss of vision.  I tried multiple times to close and restart app with no success of regaining connection.  Using RTH is very rare for me.  Never being able to gain a connection with the Mavic Pro during RTH even when feet away.  After landing, I turned off the Mavic Pro and restarted it with no success reconnecting.  So, I don't think it was aircraft hardware issues.  After restarting my Samsung Galaxy S8 I was able to reconnect normally.  When I first got my Mavic Pro disconnection issues were normal during flight for the first couple months before the DJI Go 4 app and Mavic Pro firmware became very stable and issue free.  This is the first time in many months that I've had an issue with a disconnect using my SamSung Galaxy S8.  Has anyone else experienced a fatal crash of the DJI Go 4 app since last update that required you to restart your phone??  Also, I close all apps before using my S8 with the Mavic so it won't have any processing issues during flight.  (side note, Mavic Pro RC screen is the Bee's Knees when you initiate RTH.  With all my Phantoms you had to hold your breath, cross your fingers, and trust the machine to come back waiting for the "bzzzzz' before you could relax.  With the Mavic Pro hitting RTH is pretty stress free when you can just look at the screen and watch the numbers fall as it returns.  I really liked that stress reliever.)

On Saturday I faced almost the same problem. Twelve minutes of flight and then disconnection! No Camera! No view!
RTH started but I was in panic and cancelled it, wanted to try landing it mannually. for that connection seems to come back, so I was holding down left stick to land. But then again lost connection, so RTH (I've set it in the settings) started again.
I was in thi situation for a couple of minutes. Managed to bring it down to about 5 feet, then I grabbe it. Connection loss, RTH started again! Cancelled it. Lost connection, again RTH.
My main worry was that I had in the settings for RTH altitude 120feet from previous flights and I was worried that It may fly away anyway.
Emergency shutdown wasn' possible, or did not work...
So I was grabbing my Mavic with full speed and no possibility to shutdown. Pressing battery didn't work either.
Tried again emergency shut off with both sticks. Nothing!
On display where appearing messages of battery overheating...
RTH started again due to connection loss. Still holding the Mavic Full Throttle.
Sigh!
Finally I called my wife to hold the remote and asked here to try emergency shutoff, but it says "disconnect"!!

So carefully and concentraded on not going in contact with the propellers, I removed the battery. And so it finished.
App was still saying, disconnected. Closed the app, opened again, worked for 30secs the again disconnected...
Rebooted controller... same thing.
The time the mavic showed connected, Battery overheat was displaying!! so I changed battery.
For a couple of time still disconnected and then after some minutes it was table again. Did not fly again that day.

Thinking on the problem, probably a safe and automatic RTH would have being the best solution. And Safest!
But as said, I was worried that letting the Mavic go I would have more troubles.

Does anyone have some feedback of similar situation happened or suggestions/ideas on how you would have behaved?
What I've learned  is that RTH altitude is better to be set before each flight. According to environment and surroundings.

Advise and feedbacks are welcome.

I am not 100 % sure, but crashing is happening in FCC mode, I tried FCC mode even though i live in Europe and crashed thrice. I had to trigger RTH from my remote.

Interesting!  Well, I was in FCC mode.  Just that over the years, disconnect has never worried after Phantom 2 issues, Phantom 4 issues, new Mavic issues.  But it was very rare I couldn't close the app and regain connetion when re-opening it.  I hope my issue was a random glitch in my S8's operation.  Everything reconnected normally after shutting it down and restarting phone. Mars5150, that sounded like a high anxiety moment!!  WoW!!  I'm sure you did, but, normally pulling down and to the far right your left stick will kill the motors.  Glad you didn't have a incident.

BengalBoy Posted at 2018-5-28 23:46
Interesting!  Well, I was in FCC mode.  Just that over the years, disconnect has never worried after Phantom 2 issues, Phantom 4 issues, new Mavic issues.  But it was very rare I couldn't close the app and regain connetion when re-opening it.  I hope my issue was a random glitch in my S8's operation.  Everything reconnected normally after shutting it down and restarting phone. Mars5150, that sounded like a high anxiety moment!!  WoW!!  I'm sure you did, but, normally pulling down and to the far right your left stick will kill the motors.  Glad you didn't have a incident.

I been having issues with  my Mavic lately, Aircraft Disconnected is quite common while flying what have not been common is that  the Mavic  wanted to land immediately when disconnected not even try to go home (go 30 feet then go home) when that happens the controller display Sys Err Chk App, it has happen to me twice already.
Imagine me trying to catch my Mavic trying to land in the middle of a lake. Thanks god it was in a not too deep area, and I could enter the lake and catch it before landed, also because it waited 3 feet hovering over the water 1 full minute before it attempted to land.

The second time I was not lucky!! it happened again lost signal, aircraft disconnected from app then from RC (while display SYS WARNING+CHECK APP) the aircraft land it directly in the middle of a river. I was not even far (15 mts)  my mavic drowned!! I could take it out and recover the flight data and black box... now I need to know HOW DO I KNOW WHAT REALLY HAPPENED??
http://www.phantomhelp.com/LogViewer/6CIF35Q11NC51UBSNKZJ/

Flight data will be saved on your mobile device and I suggest you upload and analyze using one of the online flight data companies to see what your log says?

Had the disconnect last weekend (also on samsung s8+) near the end of 2nd battery. RC was still connected and AC was ~200m away. I consider the display of the RC indespensable in such situation and huge plus over other dji drones. Reluctant to use RTH and surrender control, I brought the AC higher up and used the right stick and the distance indicator to determine attitude and bring it back to land. Restarted RC and AC and had connection again, but not enough battery for another flight. Good thing it happend relatively close (was much further away during the flight) and in known surroundings.

martin joãoo Posted at 2018-5-30 06:07
Had the disconnect last weekend (also on samsung s8+) near the end of 2nd battery. RC was still connected and AC was ~200m away. I consider the display of the RC indespensable in such situation and huge plus over other dji drones. Reluctant to use RTH and surrender control, I brought the AC higher up and used the right stick and the distance indicator to determine attitude and bring it back to land. Restarted RC and AC and had connection again, but not enough battery for another flight. Good thing it happend relatively close (was much further away during the flight) and in known surroundings.

Sounds very similar to my experience.  Did you have to restart your Galaxy S8 to re-establish connection with DJI Go 4 app?

No, I didn't restart the phone, just the app.

Same happens to me this time with a s8+ . First in about 200 mts distance the drone lost connection with the app , full black .. but the remote was able to bring it and to land it with my control . Second time the drone was about 10 mts from me and lost connection but this time the remote can not control the Mavic . press the RTH button but noticed  that has a eletric cable over me . if the mavic goes up to RTH in about 30 mts it goes into the cables . Cancel the RTH and imediatly i can control the drone again ... Enough for today .. i had a Spark with connection issues and bought a Mavic Pro because of almost non existent Lost Signal issues .. Pretty scare to fly again and lost it or damage

Got back from a week flying in Cozumel.  Had the disconnect occur on two different occasions while flying.  Both times the aircraft refused to reconnect with the DJI Go 4 app requiring me to land and restart my Samsung Galaxy S8.  Very frustrating to lose confidence in my Mavic after so many months of flawless operation.  I'm not sure what has happened by the last DJI GO 4 update suddenly has created this "disconnection error" between my Mavic Pro and Samsung Galaxy S8.  I've flow several batteries with no issues, however, when it does happen, its not a recoverable error and requires a hard reset of my smartphone to regain a connection.

I lost my drone due to this on Sunday. App gave high cpu warning, froze and didn't come back. Closed it, re-opened and it wouldnt connect to the drone. Battery was quite low already (maybe 40%), and I panicked - not sure whether the drone would already have been in RTH I was unsure whether to press the button. I eventually did, but the drone never made it back . Do I have any recourse here with DJI since their app crashed / wouldn't reconnect to the drone ?