Can no longer download photos from Canon SX50HS to I-photo

I still have no idea why I have been able to download directly from the camera for the last several years with no problems but last night I couldn't

Which system version do you have installed? Did you upgrade to Mojave? Or what else has changed?

Downloading from a camera can be problematic, if the battery in the camera is low, or the mode switch is set incorrectly, or some of the software you are using is incompatible.

The next time you cannot import directly to iPhoto from the camera, launch Image Capture to check, if it is only iPhoto, that cannot access the camera.

But using the card reader makes importing much easier. Does your iMac not have a built-in card reader slot? All iMacs I owned had a card reader built in. Or does the card from your Canon have a different format and does not fit into the slot?

Well next thing is to reformat the card with the camera - this takes a couple of seconds. And rather than deleting the images from the card after transfer, this is what you should do. It erases and resets the card, and this leads to less issues in the future.

I used a Weme card reader that I have had hanging around for years, with no idea what it was for. Used it on the card that I could not upload my 600 images of a recent visit to the Amazon River. I hooked it up directly to an available USB port on my iMac, and I was able to get the job done. I have no idea why it is taking so long to complete the import, but I am glad it worked. Something Apple did with iPhoto and recent upgrades to the Sierra OSX probably screwed things up. I wish they would fix this bug so that I could upload directly with the software in iPhoto on the iMac.

Something Apple did with iPhoto and recent upgrades to the Sierra OSX probably screwed things up. I wish they would fix this bug so that I could upload directly with the software in iPhoto on the iMac.

More like the card needs reformatting. You do this with your camera (it's an option in the menus.) As a general rule it's the best way to clear a card and keep it in good condition.

Going forward: The Sierra OS is three years old and superseded twice over, and iPhoto hasn't been developed or sold for almost four years now, having been replaced by Photos.pp so there will no updates to that either.

So, in effect, my iMac OSX, which is at the end of the line, and unable to accept operating system upgrades, has reached the end of its support to users. This is telling me that I need to buy the newest and latest iMac. This brings in the question as to what Apple is doing to support new desktops, since it has done nothing in the past several years to bring out new and dynamic improvements to its desktop line. The once great Apple that I have known is starting to rot at its core.

No, it's not telling you any such thing. What it is telling you is that you need to reformat the card with the camera. Also, frankly, having upgraded my iMac recently from one even newer than yours to the current 27" model, I think you'll be surprised by the development and improvement.

I did reformat. Rather than reformat my card (which has 600 images from a trip up the Amazon river) and erasing them all, I put in a separate card, reformatted it, took a few pictures, and attempted to upload them - with the same result - unable to because of invalid data or other problem. The problem exists with my older iMac, which is running on High Sierra 10. 13.6, which after the last upgrade or update, is unable to conform to the new Photo application (after the old iPhoto application). There is no workaround, or fix right now. The Apple Creative Development people are going to call me later to discuss the issue. I'll see where it goes from there. If there is no fix, I may have to purchase a new Mac Mini, which could resolve future issues when my desktop is again so old that it is beyond support.

Several possibilities but among the common fixes: try use a USB card reader rather than directly connecting to the camera.