Xcode – Codesign wants to access key “access” in your keychain, I put in the login password but keeps asking me

Normally the "cleansed" version of the file system that the Keychain's Get Info dialog presents to you won't allow you to access the hidden /usr/bin directory, but I found a way around this.

1. Get normal Finder windows to show all files. If you aren't aware of how to do this, check out this article.
2. In a normal Finder window, navigate to /usr/bin
3. Drag bin over to the Places area in the sidebar. Now bin is a shortcut you can access from anywhere.
4. From within the Keychain's Get Info -> Access Control pane, click the "+" button to open the find application dialog.
5. Click the bin that is now under the Places on this sidebar.
6. Navigate to and select codesign.
7. Click the Save Changes button.

In my case I went to Keychain Access, selected "system" in "Keychains" (top left). Then for each item: right click, "Get Info", "Access Control" and added Xcode in "Always allow acces by these applications:" list.

(I'm not using MonoDevelop, but guess the problem reason is similar)