When attempting to connect using SharePoint Designer 2010 to a SharePoint 2010 server that is low on available physical RAM, you may receive the error “The server could not complete your request”, despite the fact that the site is still loading via the browser.
However, the information provided in the “Details” section is anything but useful, as it is completely empty.
Using a sniffing program such as Fiddler2 or Wireshark to look at the requests that are being sent to the server reveals that the following POST statement is receiving an HTTP 500 error:
POST http://site.com/_vti_bin/client.svc/ProcessQuery HTTP/1.1 HTTP/1.1 500 System.ServiceModel.ServiceActivationException
Browsing directly to the webservice then reveals the true root of the issue:
“Memory gates checking failed because the free memory is less than 5% of total memory. As a result, the service will not be available for incoming requests. To resolve this, either reduce the load on the machine or adjust the value of minFreeMemoryPercentageToActivateService on the serviceHostingEnvironment config element.”
SharePoint Designer can hit a server quite hard with a large number of very resource-expensive requests, so this memory gate protects an already heavily-loaded server from getting pushed over the edge, causing it to start returning errors in normal user-space. While it does give a setting to change as a workaround, this is not the correct solution, as it puts the stability of the environment at risk. Either find out what is burning so much RAM, do what you can to offload heavy applications or services to other machines, or bite the bullet and add more RAM.
Memory gates checking failed because the free memory (539389952 bytes) is less than 5% of total memory. As a result, the service will not be available for incoming requests. To resolve this, either reduce the load on the machine or adjust the value of minFreeMemoryPercentageToActivateService on the serviceHostingEnvironment config element.