Last night, ehrrm ... this early morning, I was trying to get the .NET Framework 3.5 June CTP that was released a couple of days ago installed on one of my dev machines and I can't say that it installed smoothly and without issues.

Working with new sofware that is provided in early stages is a great thing to do. You get the opportunity to testdrive the upcoming releases (sometimes it is not even released in the end) by installing Beta and CTP software on your test machines. You do have to take in account however that it can consume a lot of your already limited amount of time 'cause you may run into all kinds of unexpected issues that you have to solve first.

That happened when I was installing the 3.5 June CTP NetFx. The installer failed to work and I was able to track back an error log containing something like this:
DepCheck indicates Microsoft .NET Framework 3.0SP1 WF (CBS) is not installed.

To solve the installation issues I found some related comments that the error may be caused by some installed 'fixes' (KB110806, KB930264, KB929300).

For me removing these indeed solved my problem and I was able to install the 3.5 June CTP .NET Framework without errors after that. So if you have similar behaviour when installing the June CTP try this for yourself.