I can manually 'Locate Referenced Files', though for 10,500 images this is slightly impractical!
Hi Andrew - it's probably not nearly as bad as you think. I was recently in a similar-ish position, where I needed to relocate a bit over 5000 referenced images, spread through over 300 projects. I had
cloned my referenced Photos archive from my iMac to my laptop and installed Aperture there too. Although the various file and folder hierarchies were the same, of course the UUID for the two hard disks were different and the masters were not linked. I initially located the referenced files on a project-by-project basis and found this worked. Synch up one file and the rest of the files in the project followed along.
I then discovered that I could do this at the top level of my Aperture hierarchy - a series of folders, one for each year. eg 2010, 2009, 2008, etc containing the various projects. Again, synch up one image file from the whole year and the rest automagically followed along. I was happy to do this for each of the remaining folders (years). I was very happy that it was going much faster than doing it on a project-by-project basis.
The next time I do this (to bring the laptop in line with my 'production' machine), rather than proceed through the ten folders one at a time, I'm going to go to the Photos group up at the top of the inspector - the one which shows you every single photo in the system - and try it there. I'm fairly confident that it should work. Identify a single image and find it's corresponding file. Then tell Aperture to do the entire selection. Once kicked off it may take 20 or 30 minutes, but I can wonder off and do something else.
It was smart enough to cope with differing paths for the masters. For example, the following image file paths can all be resolved in one go:
/Users/Gary/Pictures/CanonPowerShotG9/2008/2008
0510-Castle
/Users/Gary/Pictures/CanonPowerShotG9/2008/2008
0712-ParkVisit
/Users/Gary/Pictures/LumixDMCG1/2009/2009
0810-CountryWalk
/Users/Gary/Pictures/FujiFinePixEXR200/2010/2010
0203-InTheOffice
I don't know what might have happened in your upgrade process to cause this to happen in the first place, but sorting it should be quite straight forward. Good luck!
Regards,
Gary