I recently installed and used MiKTeX successfully on a brand new Windows 10 laptop. However, I had trouble with Asymptote. The first time I ran Asymptote from the command line, I typed this:
asy -f pdf cos.asy
I got a long string of errors that all looked similar to this. This was the first one:
Sorry, but "MiKTeX Configuration Utility" did not succeed. The log file hopefully contains the information to get MiKTeX going again: C:/Users/Mike/AppData/Local/MiKTeX/2.9/miktex/log/initexmf.log
Looking in the log, there are messages about inability to access files because they are in use by another process. A sample message follows:
2016-04-05 00:27:32,294-0700 FATAL initexmf - Windows API error 32: The process cannot access the file because it is being used by another process. 2016-04-05 00:27:32,294-0700 FATAL initexmf - Info: path="C:\Users\Mike\AppData\Local\MiKTeX\2.9\miktex/data/le\0cd9538597225e8c88eaf4782d2437f2.fndb" 2016-04-05 00:27:32,294-0700 FATAL initexmf - Source: Libraries\MiKTeX\Core\File\win\winFile.cpp 2016-04-05 00:27:32,294-0700 FATAL initexmf - Line: 275
To my awareness there were no other programs running that could have been using MiKTeX. Also, a reboot did not change the behavior.
UPDATE: uninstalling and reinstalling MiKTeX fixed this. No more need for an answer.