The problem is I frequently fails when compiling source code or packaging android apk due to the target file is unable to write or create, mostly the target file is UnrealBuildTool.exe or ProjectName-debug-unaligned.apk, sometimes sth.dll . And I found out that these files of old version on the disk were unable to delete or rename when this happened, the windows 7 system told me that I didn’t have the administrator authentication to operate these files. My work environment is win7 64 bit and logon as a member of Administrators Group. If any Experience or Advice come up to you , please tell me, thank you.