Hello I have experienced the following unexpected default behavior when installing cygwin inside my home directory. Using the --no-admin option and choosing "just me" in the setup. As user1 when installing cygwin to: "C:\Users\user1\Downloads\cygwin_test1\" Then all the directories and files have the read and execute permissions for the "Everyone" SID. This means a user2 on the same system can read files inside "C:\Users\user1\Downloads\cygwin_test1\home\user1\" It also means that user2 can use stuff in the cygwin install such as bash, even though I did not intend for that to be available to user2. The above applies both to the newest cygwin setup from the cygwin website as of this writing, and also to the 2.921 setup. I have worked around the issue myself by setting the permissions manually after the install. So I am just writing this to inform you that I found the behavior unexpected, and then you can determine if you consider it a bug or not.