BMC Client Management 12.8 upgrade setup crashes if KB2999226 is not installed on system. BMC Client Management 12.8 Upgrade (mtxsetup.exe) stops, error details indicate that api-ms-win-crt-runtime-l1-1-0.dll is not present or does not contains a specific entry.
(Reproduced on Windows 2008 SP2).
The new compiler used for building BCM 12.8+ versions requires the Microsoft Universal C Runtime (UCRT). Agents cannot be deployed nor they can be updated unless the UCRT is installed.
Note that recent operating systems should automatically include this new runtime while older ones may need to be patched with KB2999226. Following link allow you to identify the requested KB. Download it and install it on your systems before running 12.8 upgrade: