Short answer is yes it should work. Longer answer is that we have identified an issue on the 6500A where the CD software (which is required for button support) may be causing conflicts, while the In-OS software provided by Apple Software Update (which doesn't have button support) works fine. They are still investigating that. As for the response from the Scan guy on the Mac team, here is what he replied to me with:
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I just went out to the forum and it appears that TheMacPhotog last posted on the 27th. If I understand their current situation:
* Connection is via WiFi
* Printing works fine
* Since reinstall, scanning from HP Scan works partially (can scan, but sees only 200 ppi as a resolution option)
* Scanning from buttons still doesn't work
Regarding the 200 ppi, HP Scan must successfully communicate with the device in order to obtain a complete listing of the supported resolutions. Until this happens, 200 ppi is the only option in the list. The fact that invoking a scan in this situation is successful is a bit surprising to me.
Regarding the scan buttons, here again it seems like there is a partial communication taking place. The fact that a scan can be invoked from the device and result in the launching of the Automator action indicates that the Mac is successfully subscribed to the device for scan events. But obviously something is preventing successful completion of the scan request.
My first inclination would be to check the selected device in the software for both of these cases.
For HP Scan: Open HP Scan > Preferences to the Scanning tab. In the Scanners popup menu, choose "Browse Scanners". In the window that is presented, make sure that the intended device is selected and then click "Continue". If things are working correctly, the Resolution popup menu in the Scanning tab should contain multiple resolution options.
For Scan buttons: Open HP Utility. Make the 6500a the active device. Under "Scan Settings", select "Scan Shortcuts Manager". This will present the list of available scan shortcuts. At this point, I suggest testing one of the shortcuts (e.g. Save as PDF) to see if the scan can be successfully completed from this launch point. If running the scan shortcut from here succeeds, then I suggest clicking the Edit button and confirming the selected device (same basic UI and procedure as in the HP Scan case, just now presented in the context of the Automator workflow).
Not sure if performing these steps will be sufficient to get the software back on track, but it might at least help us to better isolate the root cause.
I'm also interested to know if Image Capture scanning works for this customer. Since the same underlying drivers are used to support both Apple's and HP's scan solutions, it would be useful to know if Image Capture is also exhibiting odd behaviors.
BTW, the requirement to install scan components from Custom Install didn't kick in until products released after the 6500a. Easy Install for this device should install the software required for full scan support.
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So if you want to try his suggestions and get back to me, we'll see if we can't get you working.
Just trying to help.
Andrew