Can't update to latest software, it says "your operating system has been modified".

[AC Question]

I am unable to update from 5.0.2 to the latest on my samsung galaxy s6 edge, it says that my operating systems has been modified in an unauthorized way. But when i go to
settings > about device > status
It shows that my device status is official.

 

[H3aTeRzz]

Hi

Was your device rooted, but then unrooted ? If the system was altered by root, and you didn't do a OEM Flash of the software to restore it, then it still leaves fragments of the root....thus preventing the OTA update.

 

[Rukbat]

And flashing a Samsung phone is, at very worst, boring. See [Samsung] How to flash Stock ROM via ODIN. (Back up EVERYTHING first - see Backing up an Android Device.)