There is a maximum 50MB size limitation on the XML report file to import. If you've ever try to import something and it just stopped without giving any kind of error, then please check to see if the XML file size is larger than 50MB.
If it is, you may need to change the maxRequestLength. This setting is found inside Analyzer’s web.config file (Program Files/Analyzer/Web). You will need to restart Analyzer for the effect to take place.
<httpRuntime executionTimeout="550" maxRequestLength="50000" />
You may set the maxRequestLength to -1 to for unlimited size.
Due to IIS7 added security, you will also need to add the following to the Analyzer Web.config for the maxRequestLength value to take effect:
For additional information please see this Microsoft link: