ERROR: The installer was unable to read the file "Diablo III\msvcp90.dll" this error can be caused....
I recently reinstalled Diablo 3, by running the diablo 3 installing disk. Fix #2Right click on the Diablo 3 setup file you downloaded via the Blizzard Downloader Select Properties Choose Windows XP (Service Pack 3) (Note: Does not work on Vista.)Right Click the Icon, Run as Administrator. Delete your C:\Program Data\Blizzard Entertainment\Cache folder. Run the Downloader again, as administrator, and see if it gets past the “Updating Setup Files” window. Start the agent application manually and after that start Diablo III setup file in your Diablo-III-8370-en GB-Installer folder.
Graev was unable to play Diablo 3 during the beta due to a problem with the launcher giving an error. it will get stuck for a min or so and then work Fix #5 (Thanks SCH) NOTE: This Fix is experimental. Proceed with Fix #5 at your own risk, “I followed all of the posted fixes and none of them were working for me.
After pre-ordering tonight and downloading the client to be ready for Tuesday, we ran into the same problem and thought all hope was lost. Close it, and ctrl alt delete and end the “Agent” process. Go to C/programdata/battle.net/agent and run the “Agent” executable 4. An user on the forums posted his version of the C:\Program Data\Battle. All you have to do is replace his version with your old version, and hopefully everything should work (as it did for me).” -SCH from comments - Fix #5 Additional Notes: If you get a decryption error it means you probably didn’t finish the download. decryption error might also indicate a corrupt download.
I've tried all the solutions posted here nothing works...error message, updating setup files just gets stuck indefinitely halfway through.