Q: Problem since upgrading to yosemite with photos and i movie

Hey there Gaffa2802,

It sounds like you are needing to add videos you have in Photos to your iMovie project. You should see a section in your Librarys called Photos Library from which you can do so, according to the iMovie help here:

Add photos and video clips from Photos, iPhoto, or Aperture

Add media from your Photos, iPhoto, or Aperture library

1. In the Libraries list, select your Photos, iPhoto, or Aperture library.

2. Click the pop-up menu at the top of the browser, choose a content category, and then scroll through the thumbnails of photos and video clips in that category.

3. Select the photo or clip you want to use to see a preview in the viewer.

4. Do one of the following:

    
    
   •  

     Insert the photo or video clip: Drag it to the timeline between clips or between a clip and a transition.

       

     As you drag, a blue box appears in the timeline, indicating where the photo or clip will appear in the timeline.

      
    
   •  

     Replace a clip: Drag the photo or clip on top of a clip in the timeline.

       

     As you drag, a white border appears around the clip in the timeline. When you release the mouse button, choose Replace from the menu that appears. The photo or clip replaces the clip in the timeline.

      

Thank you for using Apple Support Communities.

That's definitely unexpected behavior. Next I would have to recommend removing iMovie from your computer:

OS X Yosemite: Install, update, and uninstall apps

Apps downloaded from the Mac App Store: Click the Launchpad icon in the Dock, hold down an app’s icon until all the icons begin to jiggle, then click an app’s delete button . If you later want the app, you can reinstall it from the Mac App Store.

Then restart your computer and download it again and look for that libraries list:

Mac App Store: Finding your purchased apps

Apps purchased via the Mac App Store

When purchased via the Mac App Store, apps are installed in the Applications folder. Icons for purchased apps are automatically placed in the current user's Dock. There is also a purchases tab in the Mac App Store where you can see all of your Mac App Store downloads.

If the issue still persists, I would reach out to Applecare for some additional assistance:

https://getsupport.apple.com/GetproductgroupList.action.

No worries at all Gary! 

I movie was installed on the mac when i purchased it.

Would i have to pay for it if i uninstall and reinstall?

 It depends on whether or not you already have iMovie in your Purchases in the Mac App Store. You can check that in this way:

Mac App Store: Finding your purchased apps

Apps purchased via the Mac App Store

When purchased via the Mac App Store, apps are installed in the Applications folder. Icons for purchased apps are automatically placed in the current user's Dock. There is also a purchases tab in the Mac App Store where you can see all of your Mac App Store downloads.

If you do not see iMovie there, you should check to see if it is Hidden using iTunes:

Hide and unhide purchases in the iTunes Store

Unhide your purchases

On your computer

 

1. Open iTunes or iBooks on your Mac or PC.
2. Click iTunes Store or iBooks Store.
3. If prompted, sign in with your Apple ID and password.
4. In iTunes, choose Store > View Account from the menu bar.
   In iBooks, choose Store > View My Apple ID.
   You might be asked to enter your password again.
5. On your Account Information summary, scroll down to the iTunes in the Cloud section. Click Manage (to the right of Hidden Purchases).
   
6. From the upper-right hand corner of the Hidden Purchases window, click on a content type (Music, Movies, TV Shows, or Apps).
7. Below the item you want to unhide, click Unhide.
   

If it is not in Purchased, nor hidden you may have the option of Accepting the apps based on when your computer was purchased. This article will help you do that:

Accept bundled apps using the Mac App Store

Accept your bundled apps

Follow these steps to accept bundled apps with your Apple ID.

1. Open the Mac App Store.
2. Click the Updates tab.
3. Apply any updates you see listed there. 
4. Click the Purchases tab.
5. Click the Accept button next to each bundled app you see listed.
6. Sign in with your Apple ID if prompted.

After you accept the apps, check the Updates tab of the Mac App Store again to see if any updates are available for these apps.

Now, if none of the above either shows the application in your purchases, or redeems them to your account, and if you received two discs with your computer when you bought it, you should be able to reinstall iMovie from disc two called Applications Install DVD. 

Mac OS X 10.6: Reinstalling applications that came with your computer

To reinstall an iLife application (iPhoto, iMovie, iWeb, iDVD, or GarageBand):

• Insert the Applications installation disc into your computer’s optical drive (or an optical drive connected to your computer) and double-click the Install Bundled Software icon.

Note:If your computer came with an iLife installation disc or you purchased a newer version of iLife, insert that disc instead, and then follow the onscreen instructions.

• Follow the onscreen instructions. In the Installation Type pane, click Customize.

• Click the disclosure triangle next to Bundled Applications, select the checkbox next to the application you want to install, and then click Install.

Apologies for the wall of text but, there are many variables here to take into account.