I had recently updated a custom Master Page. When trying to open this Master Page in SharePoint Designer I received this error.
soap:ServerServer was unable to process request. —> The file http://server/sites/site/_catalogs/masterpage/xxxxx.master does not exist.
I could see the page in the list however I couldn’t open it. All other files appeared do be fine and would open normally.
Back in a web browser I tried manually checking out the Master Page from the Master Page Gallery, which worked fine. However when I tried to check the file back in again it errored.
There is no file with URL ‘_catalogs/masterpage/xxxxx.master’ in this Web. at Microsoft.SharePoint.Library.SPRequestInternalClass.CheckInFile(String bstrUrl, String bstrWebRelativeUrl, Int32 iCheckinType, String bstrCheckinComment, Boolean bIsMigrate, Int32 iEditorId)
at Microsoft.SharePoint.Library.SPRequest.CheckInFile(String bstrUrl, String bstrWebRelativeUrl, Int32 iCheckinType, String bstrCheckinComment, Boolean bIsMigrate, Int32 iEditorId)
In the end I had to manually re-upload my custom Master Page into the Master Page Gallery.
This has fixed the issue however I am still unclear as to why it failed in the first place.