I have updated 2 PCs to 1803 the first had already 18.4.1 installed the second was with 18.2.1. Both updated to 1803 absolutely without problems (have rebooted multiple times) and I have subsequently updated the PC with 18.2.1 to 18.4.1 again without problems.
Did notice though that some of the Radeon Settings were put back to default after the 1803 update.
clean install 10 with 18.4.1 drivers all i done with 1 that's been throttled & crippled by nvidia drivers. Havnt had an issue with 1803 with 18.4.1 on a R9 270
On my side it started with the 18.5.1 drivers, bootloop and i cant hear my pci soundcard beeing activated trough the time. also my mouse and keyboard are shut off because of the drivers.
I am suffering exactly same problem as open post with Vega 56. Driver 18.2.1 work, but nothing after that. And I have tried all drivers except 18.8.2.
I have installed new windows, changed power, changed ssd etc. Nothig works.
Same here Circular Loop. Cannot start the computer.
I had so many issues getting these drivers to work on VEGA 64, Asus B350M, Ryzen 1600.
Have not updated since the Summer. Before I could just roll back, but now it stuck in a circular loop.
Download the driver you want.
Disable fast startup on Windows 10 only.
Run DDU from safe mode. Get it from WagnardSoft_com.
Disconnect from the internet. ( this is the key as it is Windows update screwing up the driver and causing the loop)
Restart, and install the driver.
Restart with internet back on and you should be good to go.