You are probably reading this article because you got one of these messages telling you that ADE can't save one of the Bgl files.  ADE tests the folder(s) you want to compile to and if it cannot save to them it will generate these messages

The most likely reason is that your flight simulator is installed in the default folder.  This is inside C:\Program Files (x86)\   This folder is subject to User Access Control (UAC.  UAC was introduced with Vista and is designed to protect you from unwanted programs writing files and data that might introduce spam or other problems.  By default Microsoft arranged for flight sims to be installed in this default folder even though flight simmers often want to add or change files.  ADE cannot save to these folders.

The simplest method is to start ADE with elevated privileges.  Right Click The ADE Short Cut and select Run as administrator from the menu.  You will see the UAC dialog asking you whether you want to run ADE.  Click Yes and ADE will start.  You should now be able to compile to the protected folders.  The advantage of this method is that it is easy.  The disadvantage is that  you must remember to do this each time you start ADE.

You may wonder why ADE just doesn't start with elevated privileges.  Well the whole point of UAC is to stop unwanted programs interfering with your operating system and if programmers could just bypass it then it would not be much use.

NOTE that depending on the access rights of your user profile in windows it is possible that you may not have access to this option.

Some folks feel comfortable turning off UAC and managing security themselves.  You can do this and if so then you don't need to Run ADE as Administrator.  However other program may be able to make changes that you are not aware of.  We don't recommend turning off UAC but if you decide on that route the process is simple enough - just Google "Turn off UAC"

is also the biggest bind.  That is to uninstall FS and re-install it in a folder outside the UAC areas and preferably not in your C drive if you have other partitions.  Most simmers who are aware of the issues will install away from the default folder and away from UAC.