While Apple includes a screen-sharing service in OS X to provide a remote desktop option, there are several other options available for implementing this in OS X, including TeamViewer, Timbuktu Pro, and chat programs like iChat and Skype. While these tools should allow you to control a Mac remotely, some may interfere with various system settings and prevent you from customizing aspects of your Mac.
Recently MacFixIt reader "Ed" wrote in asking us about a problem with using Timbuktu Pro to access a remote Mac, in which the system would revert any changed screensaver timing settings:
A friend has an old PPC iMac running 10.4.11. Somehow, it is stuck in the mode of requiring a password to unlock the screensaver. I have un-checked the "require a password" in the security section of system prefs. I have tried locking system prefs and not locking system prefs. I have run repair permissions and verify disk with disk utility. Everything shows up okay -- except when I restart or log out. The system prefs come back with "require a password" checked.
Usually when these type of problems happen you can address them by removing preference files that may be involved either directly or indirectly with holding the preference setting. Therefore, we initially removed the various screensaver preference files from the system:
After doing this and seeing no change in the behavior, we tried removing some less likely preference files, including the hidden .GlobalPreference.plist files in various preference folders (these hold some display-related settings), and resetting the system's PRAM (this needs to be done locally), but those did not help the situation either.
The solution ended up being to use TeamViewer instead of Timbuktu Pro to control the Mac and modify the stubborn settings. While it is odd that a remote desktop program would prevent a setting from being saved, sometimes the background services involved in running the application may have a bug or other limitation when interacting with settings.
If you are using a remote desktop program and find that some features or settings are not working as expected, try changing to a different tool to see if the issue goes away. Standard VNC clients like Apple's Remote Desktop or Screen Sharing may require some special settings for network hardware, but others, like Skype, do not require as much setup.