Thank God for Time Machine !

[Anastasius]

Somehow, somewhere along the line I corrupted my iPhoto library. Might have been trying out something or other..no idea. Last access was 18 November .Seem to recall playing around with El Capitan then..whatever. Bottom line. I lost all my photos since 2010. And because both of my copy routines are Smart, that means that they faithfully backed up the erroneous changes.

Time Machine

Went back to a copy of the library on 11 November and restored it.

Perfect.

[MrGongGong]

Some people can drive at 90 mph in thick fog while drinking a pint of sherry
Luckily it seems to have worked for you this time

[Dave2002]

Some people can drive at 90 mph in thick fog while drinking a pint of sherry
Luckily it seems to have worked for you this time

It does work sometimes!

I suggest you get the photos and everything you really value backed up by another method as well - as soon as possible. I have been facing similar issues. If you're not bothered about privacy etc. you might want to try cloud storage which might give you an extra safeguard.

Otherwise use multiple copies and organised structures of photos you really want to keep.

I may have lost (mislaid?) some photos recently, but with luck they may still be on the original SDHC cards.
I have just bought yet another 2 Gbyte drive to try to clear space off my MBP - this time a WD Passport, which seems quite good so far, though it's early days yet. A previous WD rdive I had years ago failed within 10 days. Keeping data secure and intact can become almost a full time occupation.

Glad you recovered the photos this time.

[MrGongGong]

It does work sometimes!

Indeed
When it works it's brilliant
but when it doesn't you can lose everything

[Dave2002]

Indeed
When it works it's brilliant
but when it doesn't you can lose everything

Indeed - again.

You can also lose everything whichever backup system is used if a drive fails, as happened recently in a small organisation I know. Fortunately no data was actually lost, and a new backup drive was bought immediately as a replacement. I am now recommending multiple drives and a somewhat more interventionist protocol to reduce the risks if similar failures happen in the future, but the protocols will require more user input than simply connect and forget, and getting people to actually follow a strict enough regime to ensure data integrity requires effort, and also training in the software being used.

I know people who have lost a substantial amount of data through hardware failures. One lost a lot of music tracks due to an internal drive failure in a new iMac. Large drives encourage one to put more on them, but the loss is greater if they fail.

For photos, if they're non controversial - which I assume most people's will be - sites such as Box and Flickr can be helpful. I know people who use Dropbox, and I thought of using that, but I aborted installation when it started asking for privileges on my machine which I didn't think it should have.