Windows 7 and Windows Vista use security features that prevent users from editing files in system locations. This includes programs that are installed in the "Program Files" directory which includes MATLAB. When you try to edit the files in MATLAB, one of possibilities can happen:
1) User Account Control prevents the change from occurring unless you run the program with administrator rights.
2) User Account Control allows you to make changes, but redirects the changed file to the user profile using File and Registry Virtualization.
The first issue usually manifests itself if you attempt to install an add-on to MATLAB using a MATLAB file installer such as in the MATLAB connector. For this you will receive an error message indicating that you do not have write permission or a warning message stating that you do not have administrator rights. To resolve these types of issue, you can run MATLAB with elevated permission by right clicking on your MATLAB shortcut and selecting "Run as Administrator".
For the second issue, you will notice that when you have already made a change to MATLAB (editing the path, installing a new toolbox, updating a license file) if you restart MATLAB, it acts as if the change never occurred. This is because changes done without the "Run as Administrator" option are redirected to your user profile. In that case, you may have two versions of some of your MATLAB files. To resolve this you can remove the duplicates, or replace the original file with your changed version. To locate the user version of the file, you can perform the following:
1) Go to the Start Menu and type the following in the "Start Search" box:
Press Enter to open the folder.
2) In the VirtualStore folder navigate to the Program Files directory to MATLAB, to the folder that corresponds to the release of MATLAB you are using.
Once you have located the files, you can either remove the duplicate or move the duplicate into the actual MATLAB folder (ex: C:\Program Files\MATLAB\R2010b). Once complete, MATLAB will see the changes you made on the next restart.