Q: Why do I get the spinning color wheel so often when I have i photo open.

First, back up your hard disk, not necessarily that there is any reason to suspect it is failing, but the behaviour you describe can presage an impending disk failure and you should have backups anyway.

Apple Support Communities contributor etresoft wrote a very useful app to quickly gather certain system information that may help point to a cause of this problem. Go to his website, download and run EtreCheck:

http://www.etresoft.com/etrecheck

Etrecheck will be in your Downloads folder. Open it from there. You may see the following dialog box:

Click Open - etresoft contributes to this forum frequently and can be considered a trustworthy developer.

It will take a moment to run as it collects its data.

Copy and paste its output in a reply.

Do not be concerned about anything that says "Problem" or "failed".

EtreCheck was designed to remove any personal information (such as your computer's name and serial numbers) but if you see anything that looks like an email address or any other personal information that should not be divulged to others, please delete or obscure that information when you post the reply.

When you are finished with EtreCheck, quit the program. It occupies very little space, and you can keep it or drag it to the Trash as you wish.

What version of iPhoto are you using and what system.

As a test  launch iPhoto with the Option key held down and create a new, test library.  Import some photos and test to see if the same problem persists. Does it?

OT