One day lately our dev server started acting very strangely. No configuration settings were changed the previous day. Nothing was deployed to the site either.
Symptoms: all custom web parts cannot be imported because they aren't registered as safe. They are registered in the web.config as safe and normally are deployed to the IIS bin folder. They've since been installed to the GAC as well and are still deemed unsafe.
Application pages that use these web parts give a SharePoint version (YSOD) of "File not found".
I've removed all of the web parts from the home page with content=1 (which is a site page) and it loads but I can't add them back because they're unsafe. I can also access site settings if I type in the URL directly.
I've made sure that no service accounts were locked out and rebuilt and redeployed the web parts. I saw mention of the SSP sometimes causing this (??) so I created a new web app and tried to create a new SSP to experiment. It failed during provisioning with an error which escapes me ATM (something about not being able to access the pipe). Named pipes are enabled so I'm not sure if any of this SSP creation problem is related or separate.
Any tips or info is appreciated. I'm completely stuck.