How to preview the text inside ABC files using the Preview Pane (Windows)
These instructions should work for all versions of Windows from 7 onwards however they are given specifically for Windows 10.
I will assume you are logged in Windows as an administrator and that you have already associated .abc files with the ABC Player, i.e. when you double-click on a file with extension .abc, Windows tries to open it using the ABC Player.
Open Windows Explorer (by default, it’s the first icon to the right of the Task View on the task bar). Click on the little arrow to the top right to Expand the Ribbon. Go to the View tab. Make sure the Preview Pane box is pressed (it’s on the left side of the tab menu options). Close Windows Explorer.
Next, click on the Windows button to the bottom left of your desktop. Type regedit. The regedit (Run Command) app will come up as an option. Right-click on it and choose Run as administrator. Confirm your choice and run the app. Note: Do not mess with the Registry Editor unless you feel comfortable doing so or it may mess up your Windows completely. If what follows seems difficult do not proceed and stop here.
On the left pane, expand HKEY_CLASSES_ROOT and click on .abc.
The right-side pane will show a (Default) string associated with the ABC player and a ContentType string with value text/plain.
Right-click on an empty space anywhere on the right-side pane and choose New > String Value. Name it PerceivedType.
Right-click on the PerceivedType name and choose Modify…
Under Value Data write text then click OK. The PerceivedType string should have the value text.
Close the Registry Editor. Now each time you left click on a file with extension .abc in Windows Explorer, the Preview Pane will show a preview of its actual text content, saving you from having to right-click on the file to open it with Notepad each time you want to check its text. When you double-click on the .abc file it will open it with ABC Player, as usual.