After a server patch, the HFM (Hyperion Financial Management) Windows client could not start. Below is the error message in Event Viewer.
SideBySide, Activation context generation failed for "... HsxClient.dll". Dependent Assembly Microsoft.VC80.MFC,processorArchitecture="x86",publicKeyToken="1fc8b3b9a1e18e3b",type="win32",version="8.0.50727.4053" could not be found. Please use sxstrace.exe for detailed diagnosis.
Oracle Support suggested reinstalling VC++ Redistributable 2005. Searching for the version number brings up "Microsoft Visual C++ 2005 Service Pack 1 Redistributable Package ATL Security Update". Installing the x86 redistributable package solved the problem.