Top Tip: File extension clashes and how to detect them before you deploy...

When I used to work in application packaging (ahhh, the good old days), one of the common issues we'd hear about from our users was that "my PDFs no longer open in Adobe Reader" or "my image files no longer open in Windows Photo Viewer". The problem here is that two or more apps have a file extension associated with them. The first app is installed, and everyone is happy. But along comes app number two and it takes the file association, and the PDF/image file/document/whatever now opens in app number two by default.


This is a quick thing to show one user how to fix, but when it happens to thousands of users it can be a real headache, so it's best to know about these file extension clashes before you deploy your apps.


Here's how you can use ChangeBASE to check for file extension conflicts:

  1. First up you need to import your 'core' applications into ChangeBASE. These are the apps which are installed initially on your build.
  2. Once you've done that you need to create a "Core App List". You do this by going into the ChangeBASE options, Core App List tab, and create a new Core App List, You can call it whatever you want.
  3. Now close the options dialog, and select your core apps you just imported. Right-click the selected apps and add them to the new Core App List:
  4. The will create a new item under the "Reports" area:
  5. Now you need to tick the apps in the Core App List. By doing this you nominating these are the "source" packages for the assessment.
  6. Next you need to tick some packages under the Packages area which you'd like to conflict check against the source packages. These are the packages you plan to deploy onto the systems where the core packages have already been installed. They might well be "line of businesss" apps.
  7. Now click Assess.
  8. Once the assessment has completed you'll be shown amber issues where conflicts exist between the core apps and line of business apps. By default we'll tell you about all sorts of conflicts such as File, Registry etc, but the ones we're interested in here are file extension conflicts which will be prefixed "BPE". In the screenshot below I have added Adobe Reader as a core app, then assessed it against an app I know it conflicts with in terms of file exensions. The report shows us that there are four extensions which conflict: FDF, PDX, RMF and XFDF:
  9. The next step is for you to decide how to best manage this conflict...