Fatal Error in Version

TMS Echo fails during the compiling with this error...

[DCC Fataler Fehler] F2084 Interner Fehler: AV09E5B6F3-R00000010-0

It seems the platforms Win32, Win64, iOSDevice32, iOSSimulator and OSX32 are ok, but Android fails. This error happens in Delphi 10 Seattle, but for example Delphi 10.1 Berlin is not affected.

That looks like a bug in Delphi XE8/Seattle for Android platform. Unfortunately it’s an internal error - which means an unexpected Delphi bug in the compiler. In Delphi Berlin only it doesn’t happen (so probably Embarcadero fixed that bug in Berlin already).

You have two options:

1. Uncheck Android platform, if you don’t use it. 
2. Manually compile the packages: open Delphi, then open echo.dpk package, in echo install folder, subfolder packages\dberlin, and build the package for all platforms.