As some customers have found out the hard way, the TFS release candidates have started to expire without warning at the end of the 6 month (180 days) period. The TFS trial edition (RTM) will start to expire next month, again without warning. It also expires 6 months after installation.
This morning, Brian Harry posted a tool that you can use to detect which version of Team Foundation Server you have installed and when it will expire.
A couple of weeks ago I wrote about the impending expirations of TFS Release Candidate installations and Trial installations that were installed soon after release. Both the TFS Release Candidate and the TFS Trial Edition have 6 month expiration periods. Many of the Release Candidate builds started expiring this month. Trial Editions will start expiring in September.