Hot on the heels of not releasing a successful mobile version of Flash, Adobe is turning it’s attention back to Flash for desktop computers.

A preview release of a 64bit version of Flash Player, codenamed “Square” is now available for Mac, Windows and Linux.

Adobe advises caution when installing the app which has several known issues, including video playback problems with Hulu.com, Audi.co.uk and NBC.com.

The release also adds support for hardware accelerated rendering in the recently released IE9 beta, improving performance by up to 35%.

The release notes state that the features being previewed in Square will be available in the first half of 2011.