c# - VS2013 Update 4, can't open CSHTML files -

i have machine can no longer edit cshtml files in vs2013 update 4. exact manifestation of varies. in cases modal appear saying "the operation not completed." in cases activitylog.xml file populated errors:

system.nullreferenceexception: object reference not set instance of object. @ microsoft.html.editor.htmleditordocument.fromtextview(itextview textview) @ microsoft.html.editor.codebackgroundtextadornment..ctor(iwpftextview view, iclassificationformatmapservice classificationformatmapservice, iclassificationtyperegistryservice classificationtyperegistry) @ microsoft.html.editor.classification.razorcodebackgroundtextadornmentfactory.textviewcreated(iwpftextview textview) @ microsoft.visualstudio.text.editor.implementation.wpftextview.<>c__displayclassc.b__9() @ microsoft.visualstudio.text.utilities.guardedoperations.callextensionpoint(object errorsource, action call)

system.nullreferenceexception: object reference not set instance of object. @ microsoft.html.editor.codebackgroundtextadornment.onlayoutchanged(object sender, textviewlayoutchangedeventargs e) @ microsoft.visualstudio.text.utilities.guardedoperations.raiseevent[targs](object sender, eventhandler`1 eventhandlers, targs args)

this not appear related specific project/solution. if create brand new blank mvc solution, targeting 4.5.2 framework, opening cshtml in new solution demonstrate issue.

if create mvc solution targeting 4.0 framework, however, issue not occur. appears indicate issue mvc5 specifically.

what's particularly amazing issue had corporate re-image machine brand new hdd, reinstalled vs2013, , still see issue.

other machines in same corporate environment (ad policy, etc) working fine.

i have seen number of suggestions solutions around issue:

run vs2013 administrator: no effect.

reinstall vs2013: reinstalled whole os.

run vs2013 in safemode: no effect.

repeatedly mash face keyboard: no useful effect.

reset vs preferences: no effect.