I tried to convert my iphoto library inot photo but that failed so I am now importing the photos year by year into Photos. Can I delete the years I have converted in the old iphoto library?

Can I delete the years I have converted in the old iphoto library?

Make a backup copy of your original iPhoto Library, before you do any deleting. Mass delete is always risky. But deleting from your iPhoto Library will not remove the photos from Photos, after you imported them there.

It might be easier to find out, why you could not upgrade your iPhoto Library to Photos. What happened? Converting the library is preferable, because it will safe your edits, keywords, while maintaining the lossless workflow.

All literature I can find just suggests selecting the iPhoto Library from the list when you open Photos with the Option key. But that doesn't work for me. The Library is greyed out, even after it has been migrated. And selecting Open Photos as a response to the message "cannot open migrated libraries gives me nothing but an open, empty Photos app.

Oh yeah, and to further irritate me, Apple Support suggests that I can open the old Library in iPhoto and copy the pics into the Photos Library, but my current version won't open in Yosemite, so it sends me to the Apple Store for an upgrade, but the Store says not available. Grrrrr.

Oh yeah, and to further irritate me, Apple Support suggests that I can open the old Library in iPhoto and copy the pics into the Photos Library, but my current version won't open in Yosemite, so it sends me to the Apple Store for an upgrade, but the Store says not available. Grrrrr.

To update iPhoto:

Which version of iPhoto did you have on your old Mac? On your new Mac with Yosemite you need iPhoto 9.6.1. This version is only available from the AppStore. But apple stopped selling iPhoto from the App Store.

You can no longer buy iPhoto from the App Store anywhere, and also not update it from the "Updates" tab of the App Store. You can however reinstall it, if it is showing among your Purchases at the App Store and associated with your AppleID. It is unlikely, that you have been using an iPhoto version on Snow Leopard, that has been sold from the appStore or associated with your appleID at the AppStore.

Sign into the App Store and look at the Purchases tab. Is iPhoto listed there? Only if you see it there, can you reinstall as described in this User Tip:

Get iPhoto 9.6.1 if you didn't update before OS... | Apple Support Communities

The main idea is to move the incompatible iPhoto app to the Trash, so Spotlight does not see it as installed, reload the App Store by pressing ⌘R, and then to try to download again from the App Store - from your Purchases tab, not from the main page, since you can neither buy iPhoto nor update it, but you can reinstall, if your AppleID is associated with it.

So move iPhoto to the Trash (don't empty the Trash), relaunch the App Store. The button to the right if iPhoto should change to Install on the "Purchases" tab.

If you do not see iPhoto there, try to unhide your Purchases as described on this page: Hide and unhide purchases in the Mac App Store - Apple Support

If you do not own an AppStore version of iPhoto you will not be able to install iPhoto on your new Mac, unless you can talk the App Store Support into providing you with a redeem code for iPhoto so you can install it.

To open the iphoto Library in Photos drag it onto the Photos icon. The library may be on a volume, where Photos cannot migrate it. Move it to your Pictures folder for the conversion.