I have a Canon G9 and am trying to connect it to my iMac (Intel-based) running Snow Leopard (10.6) with the supplied USB cable to use the remote capture software. Please note, I am not trying to download photos, I want to take photos with the camera connected to my computer (allowing me to adjust the settings for the camera from the Mac). According to the documentation "RemoteCapture" will not work with the G9 (only the older G series), but CameraWindow should. Every time I run CameraWindow, the application pops up an error message stating "Failed to initialize program" and closes. I have also tried connecting to the camera from ImageBrowser (the Canon Camera link in the app), but that does the same thing. I have already tried re-installing all the software from the disc that came with the camera and updated ImageBrowser and Digital Photo Professional from the Canon website. Unfortunately, they dont appear to have an update for the RemoteCapture application. On a side note, every time I connect my iPhone, CameraWindow tries to open, but freezes. I have to "Force quit" each time.

SOURCE: Computer not recognizing my camera when connected

Most of the issues can be solved by either reinstalling the software or by disconnecting and reconnecting the device.
In this case we can close in on three solutions
1) The USB drive in the system is not functioning. Try connecting any other USB devices to the same USB port and check whether it works or not. If the other device works well then it could be a problem with the data cable or with the port in the camera (usually firewire)

2) The data cable used to transfer data might have become faulty.Try using another data cable if possible and still the same issue continues then try connecting another camera to the system and if the other camera gets detected then the problem must be with the camera.

3) Try connecting the same camera to another system and see whether the camera gets detected. If no, then the port in the camera is defective.

After this we can close in on which could be faulty. data cable / Computer / Camera.

SOURCE: Canon Powershot S2 IS is not recognized on my iMac

Simple fix...use a separate card reader to download to a folder you create on your desktop. Once there, you can move them to iphoto.

SOURCE: When I try to connect my Canon Digital Powershot

Use a card reader to download to a folder you create on your desktop.

SOURCE: "failed to initialize" camerawindow-downloading images to macbook

Do what the pros do...use a card reader to download to a folder you create on your desktop.

SOURCE: I've switched from a PC

Use a card reader to download the pics to a folder you create on your desktop. From there, you should be able to import them to any program you wish...even iPhoto.