Why can't my C# app create files in Windows 7?

Question

I have a C# app that creates a settings file for itself to store the current state of certain visual elements. This app works just fine on any machine that isn't running Windows 7, but on those machines we get an error that the settings file can't be created because the user doesn't have permission. Now, I could fix this issue by going to each computer, logging in as the administrator and giving the user read and write access on the program folder for the application that we've installed, but there has to be a better way.

It seems like in XP, you got write access on the folders you created by default, but that isn't the case anymore. Is there a setting I need in the setup package to make this work?

Answer 1

are you trying to create files in the installation folder? you should be using the user data folder for data and not the installation folders. Use the Environment.SpecialFolders.ApplicationData folder to get a folder you can write to.

Answer 2

The point is that you shouldn't be storing settings files in the program folder. Microsoft have advised against this for a long time, but started making things stricter with Vista IIRC.

Use Environment.SpecialFolders.ApplicationData (etc) to find the most appropriate place to put settings. Or use the .NET settings infrastructure which does this automatically for you.

Answer 3

You're probably running as an administrator on your non-Windows 7 machine which an write anywhere. Be sure to save any per user instance data in their AppData folder (roaming if it should follow them from computer to computer, or local if its a cache or local to taht machine only). If you need to share settings between users, use the C:\ProgramData folder with the appropriate permissions.

A program shouldn't try to store settings in its installation directory.

Be sure to use the SpecialFolders along with Environment.GetFolderPath to get the right locations needed. You should never hard code paths because they can be different between versions AND languages. (I know in the German version of XP it wasn't Program Files but Programme!)

Answer 4

This is a security flaw in your program because your program is writing information to the program directory (which is, and should be, protected.) If it's a situation of correcting the root cause, consider using the SpecialFolder enumeration or the static members on Application like like CommonAppDataPath to write your information to a more appropriate location.

Assuming the typical approach to writing a file via a path, this is a trivial fix and there's no good "expediency" reason to not correct the root cause. If you're not sure about how to manipulate the path, consider using Path.Combine(). It does it for you.

Answer 5

In general, you shouldn't be writing program data to any folder underneath Program Files (even if you created the folder). You should use the Environment.GetFolderPath(...) to figure out where to put your application specific data. You can pass in one of many enums defined here -- you probably want Environtment.SpecialFolder.CommonApplicationData

Answer 6

this app works just fine on any machine that isn't running Windows 7

Wrong! It only works on those machines if you run as administrator. I think you'll find your program is broken on Windows XP as well if you try to run it on just about any business computer rather than a home computer.

Instead, this kind of information needs to go in one of the special Application Data folders.