Photos: consolidating multiple iPhoto & Photos libraries?

[ctdonath]

I've got several iPhotos libraries (cumulative ~300GB).
Started the new Photos app on OS X with a fresh new library with iCloud enabled (yup, gonna have to pay for that). Photos gathered my Photo Stream pictures into it.
I opened a couple iPhotos libraries separately (option -> Photos) and converted those, but they remain as separate Photos libraries.
File -> Import won't let me select iPhoto nor Photos libraries. Clicking button "Review for Import" (where you'd expect the final Import button would be) complains "Nothing to import / None of these files can be imported into your Photos library".
File -> Consolidate is unavailable (gray). If I select one/all pictures, it becomes available (black), but complains "No Referenced Files to Consolidate / The selected items are already stored in the library." If I switch to another Photos library (option -> Photos), same behavior.
If I switch to another library (option -> Photos) and then Photos -> Preferences, the iCloud tab says "iCloud features for Photos are only available in the System Photo Library" (that's fine, I'm trying to _move_ these photos _to_ the System Photo Library". The General tab has the "Use as System Photo Library" button, which terrifyingly complains "Switching the System Photo Library will turn off iCloud Photo Library. / Any photos and videos that have not been fully downloaded will be removed from this Mac. Turn on iCloud Photo Library for this new System Photo Library in Preferences." with Cancel / OK buttons.

So...how to I get all my photos in disparate libraries (existing precisely because of space reasons under iPhoto) transferred into a single master Photos Library?

 

[ctdonath]

Anybody?

 

[hcole623]

Bump because I need help with this too.

I have 3 separate iPhoto libraries that I want to merge, bring into a single Photos library, then filter for duplicates, then store on iCloud.

I've fiddled with a few similar ways that you mentioned. Opening each in photos, merging with iphoto library manager then bringing into Photos. Its really bugging me.

If any dev's are listening I would gladly buy an app that does the following:

1) Import my old iPhoto libraries into this new messed up Photos library of mine

2) Skim Photos library slash iCloud library for dups

EDIT:

Wait for this:
http://www.fatcatsoftware.com/comments/announcing_powerphotos

 

[hydr]

I used Aperture to migrate three iphoto libraries to one. Opened iPhoto, made sure everything was OK.. Used iPhoto Library Utility to find duplicates, then imported to Photos.

 

[ctdonath]

MR just had an article on this. Seems the upshot is: nope, no straightforward way to really import & consolidate multiple libraries. Only hope is to export ALL the pictures from iPhoto, then import them as a mass of individual files.