Apps and extensions in Google Drive can be simple to install but tricky to delete.
Here are a couple of suggestions for getting rid of those pesky apps or extensions that you tried out and no longer want to use:
1. If the new app or extension is automatically opening your file you can: Right click on a google drive file and choose open with… then choose the app or extension you want to open the file. In most cases you will want to change it back to google docs or whatever used to be the default.
2. To completely get rid of an app or extension click the gear icon in the top right of your google drive. Click settings and choose manage apps. From there you should be able to uncheck the use as default for the app or extension OR click options and remove completely.
Hope this helps and as always leave feedback so we know if this tip was useful.