Windows 10: Remove a file association

I was trying to figure out how to open an .opx file that I crated in a much older version of PowerPoint but PowerPoint no longer supports it. As I hunted around for a program to open it, I accidentally clicked "Always use this App to open .OPX files" and hence the .opx files got associated to Word which does not recognize it. How do I remove the association so it goes back to not having an app associated?

:)

 

File Association Helper in Startup

from another forum on May 6, 2018:
You can uninstall File Association Helper in less than 5 minutes. Here are the steps to follow:

Step 1 — Uninstall File Association Helper via Control Panel

Simply go to Start > type Control Panel > double click the first result to launch Control Panel.
Then go to Uninstall a program > locate File Association Helper in the list and select it
Select Uninstall > wait until Windows completely removes FAH from your PC.
Restart your PC.
Step 2 — Clean the Registry Editor

Now that you removed the program, you also need to remove any traces or file changes associated with it. To do that, you need to open the Registry Editor.

Go to Start > type “regedit” > launch the Registry Editor
Locate the following keys and delete them:
KEY_CURRENT_USERSoftwareFile Association Helper
HKEY_LOCAL_MACHINESoftwareFile Association Helper

Step 3 — Check all the hidden files and folders

File Association Helper may have left behind various hidden files and folders. In order to completely remove the software, you can also need to delete these files. Here’s how to do that:

Simply go to Start > type Control Panel > double click the first result to launch Control Panel. On Windows 10, you can also type “Show hidden files and folder” in the search box. Then simply check Show hidden files, folders and drives and jump straight to step number 3.
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Go to Folder > select Show Hidden Files and Folders
Locate the following folders:
Crogram FilesFile Association Helper
C*Biggrinocument and SettingsAll UsersApplication DataFile Association Helper
C*Biggrinocuments and Settings%USER%Application DataFile Association Helper

4. Delete them and then restart your PC.

Step 4 — Empty Temp Folder

The final step is to clean the Temp folder where all the temporary files are stored. To empty the folder, go to Start and type the %temp% command.

This will open the Temp folders. You can now empty them. If the system displays an error message when deleting some files, leave them. The files might be in use by Windows services or some running software.

Step 5 — Use a dedicated tool to remove software leftovers

After you performed all the steps listed above, you have removed 99.9% of all the files and folders left behind by File Association Helper. However, there may be a few file that escaped your scrutiny. In order to make sure that you have removed all of them, you can also use a dedicated software uninstaller.

These applications are specially designed to remove the selected application along with all of its files and registry entries. As a result, the application will be completely removed from your PC.

There are many great uninstaller tools available on the market, but the best are IOBit Uninstaller and Revo Uninstaller so feel free to try any of these tools.

 

Remove (not change) file extension association

I mistakenly associated a file extension with .pdf. I've found many instructions on how to change (swap) the file associate from one extension to the other, but how do you remove the association completely and return it to "Choose a default" ??

This user was very helpful (How to UNSET/REMOVE a default app for file type).

I took the suggested steps above and it removed the association but didn't return it to "Choose a default" ... this has caused a thumbnail app to work for every file EXCEPT the ones i mistakenly associated, then did the work around on. This is affecting
productivity as I'm working with over 1,000 files (and growing). Since 145 people said they had the same question, please Microsoft, can you answer or solve this problem? Please help. Thanks.

 

Removing File Association that opens file with specific app

How do I reset a file to its original file association (in this case "NO ASSOCIATION")?

• I mistakenly tried to open a ".pieceshash" file [ b4ec92e20ca80c0524198cc75cededf138401f97.pieceshash ] and
• chose to open it with IE (with the check box set to always open with this app).

Now I cannot remove the file association. Please Help. Thanks