CS5 - Problem with compatibility across versions

[Circles]

Apologies if this is in the wrong section of the forum!

I'm using Photoshop CS5 to create a multi-layered, group-heavy PSD. The final file is intended for public consumption, so, ideally, I'd like it to be compatible with as many versions of Photoshop as possible.

However, I just tried to save the file, and was prompted with this message:

This document contains nested layer groups that may change in apprearance if opened in applications older than Photoshop CS5.

Opening the file in CS4 after the save confirmed that a few of the layer groups were indeed corrupt.

Can anyone shed some light on, and/or suggest a way around, this problem?

Any and all advice greatly appreciated

Thanks!

[Steve]

Go to Preferences|File Handling and make sure you check Maximize Psd and PSB File Compatibility