If you’re running Lion, with Suitcase Fusion 3 installed, you may get alerts when saving Photoshop CS5/5.5 files stating “The disk copy of […] was changed since you last opened or saved it. Do you want to save anyway?”.
These alerts occur when saving locally or to a server volume, and tend to only occur after the Photoshop file has been left in an idle state. Clicking OK when the alert comes up allows the file to save, so this false alert is more annoying that anything.
Disabling the Suitcase Photoshop plug-in will prevent these alerts from coming up. If you require Suitcase Fusion 3 to manage fonts in Photoshop, you can add Photoshop to Suitcase’s global auto-activation (if you do this, make sure to set Suitcaseas a hidden login item, as this feature only works if Suitcase is running).