Did you check this with the extensions found under C:\Program Files (x86)\Adobe\Adobe Dreamweaver CC\configuration\DisabledFeatures and it still didn't work?
Yes, we converted the extensions found in C:\Program Files (x86)\Adobe\Adobe Dreamweaver CC\configuration\DisabledFeatures from mxp to zxp files and installed them, but to no avail; Dreamweaver CC still won't open our .asp or .aspx documents.
Thanks Nithya.MV for your earlier response.
We have now found a solution at http://helpx.adobe.com/dreamweaver/kb/change-add-recognized-file-extensions.html which applies to Dreamweaver CS6 but can be adapted to DW CC. The solution was:
1. Go to C\Users\username\AppData\Roaming\Adobe\Dreamweaver CC\en_US\Configuration\Extensions.txt
2. Open the file in say NotePad (visit Preferences first to turn off Read Only if necessary).
3. Add ASP, ASPX, to the front of the list of extensions in the first line.
4. Save the Extensions.txt file (then resent the file to Real Only in Preferences)
5. Close Dreamweaver CC if it's open.
6. (Re)start Dreamweaver CC and open the required .asp or .aspx file.
This worked a treat.
Unfortunately all the other intructions provided on the Support Forum had us looking in the wrong place at:
C\Program files (x86)\Adobe\Adobe Dreamweaver CC\configuration\Extensions.txt