Parallels Desktop has been tested and should work with Mac OS X 10.5 Leopard, its developers said in a statement last night.

The developers also committed to the release of a free software update for its virtualisation software in the event any last minute changes made to the OS should cause problems.

Ben Rudolph, director of SWsoft (owners of the Parallels brand) said: "We're confident that Parallels Desktop is compatible with Leopard. Performance is great, and core functionality works smoothly. You'll be able to safely upgrade to Leopard when it goes live without worrying that Parallels will work. 

"That being said, it’s entirely possible that Apple will make some last minute changes in the final 'gold master' build of Leopard that may cause some minor bugs to pop up in Parallels. If that happens, we'll release a free, automatic update to account for them very soon after Leopard's launch."

Rudolph added: "I’m particularly excited about core features like Leopard’s top to bottom 64-bit architecture, and new user-experience features like Stacks, which should help me organize my incredibly messy desktop, and Spaces, which already works great with Parallels Desktop."

"It’s really cool to be able to work with two more OS, all in full screen mode, each in a different Space."