Windows Photo Viewer Sucks
Windows 10 comes with a range of new applications for using your files, one of these is ‘Photos’ which replaces Windows Photo Viewer (also known as Windows Picture and Fax Viewer) from Windows 7 and 8. If you preferred the old Windows Photo Viewer the good news is you can re-enable it in Windows 10. Search 'default programs' in the search feature, click 'set your default programs', find 'Windows Photo Viewer' on the left (I believe this is the application you are talking about as the Windows 7 photo viewer), click on it, then click 'Set this program as default.' Open a picture and it should open up in the Windows Photo Viewer. Windows 10 is the final version of Windows, because Windows 10 has become a service, it will be updated over time to bring new features and remove the old ones. The Windows 10 you might have updated to in July 2015 will be a different OS from Windows 10 plus all its updates a year later.
The problem is that Microsoft has all these phone app programmers and no real PC program user programmers working on theseI could name 10 things I hate about this all of which revolve around it not being mouse/desktop friendly is only useful quality is its import feature, its slow, has poor colour rendition closes the directory if I close an image to name a few but like mostof the 'NEW' it just looks pretty.its an 'app' not a real program and was probably written on a weekendI'm sure the author uses and IPhone and a mac not a windows pc!!paul. Ppsspp cheats kingdom hearts birth by sleep all commands. I'm still experiencing similar issues; either stops importing, or stops but somehow imports all or some anyway. I'm not sure why, however, if you choose to import by day, and you have more than a certain day's worth of photos on the card, this often screwsit up as well. I imagine there ought to be a fairly simple fix for this but not yet I guess(?). You can try choosing import by month and see whether this works.
Windows Photo Viewer Sucks
I've been frustrated to the point where I just use file explorer, click on DCIM, select allthen either cut & paste or drag to the folder I want them, then reformat the SD Card.