in Xcode 5, select your "TARGET", go to tab "INFO", Have a look in "Document Types" : Did you set your icon here ? Now, check if in exported / imported UTI you set the identifiers = the Type you put in "Document Types".
especially check :
com.mycomp.document.kmk != com.mycomp.document.kpk
edit : (removed)
edit 2 :
Based on apple doc here
you should set Exported UTIs :
identifier = com.mycomp.document.kmk
conform to = public.data
Additional exported UTI properties
UTTypeTagSpecification (Dictionary)
public.mime-type = Application/XXX (replace XXX vita your app name) public.filename-extension = kmk (extension without the dot)
you'll found that in your info.plist at UTExportedTypeDeclarations
<key>UTExportedTypeDeclarations</key>
<array>
<dict>
<key>UTTypeConformsTo</key>
<array>
<string>public.data</string>
</array>
<key>UTTypeDescription</key>
<string>YOUR DESCRIPTION</string> (to be changed)
<key>UTTypeIdentifier</key>
<string>com.mycomp.document.kmk</string>
<key>UTTypeSize320IconFile</key>
<string>Icon@2x</string>
<key>UTTypeSize64IconFile</key>
<string>Icon</string>
<key>UTTypeTagSpecification</key>
<dict>
<key>public.filename-extension</key>
<string>kmk</string>
<key>public.mime-type</key>
<string>Application/YOUR-APP-NAME</string> (to be changed)
</dict>
</dict>
</array>
Edit 3 :
netshark1000 have report that Application/YOUR-APP-NAME have solve the issue.
Hop this can help others.