Does Photos overwrite existing files when exporting a photo with the same file name?

Sebastian Kuhn:

«the 3rd etc. photo» will have “copy” followed by 2, 3, etc.

It is an, essentially, unending sequence.

I, too, am a little disappointed that you are not presented with a choice to do otherwise.

However, it is consistent with a certain interpretation of “ease of use”.

(Personally, I find that to be an OK default, but I would prefer to have the option to have the normal dialogue feature.)

Sebastian Kuhn:

• I would hope that the Photos App is not an exception to the above general rule!

In order to test this hypothesis, I recommend you export a couple of photos into a new folder, and test.

In order to avoid the possibility that the Photos App may consider that storing an identical photo over itself is a non-issue, I recommend changing names to be identical to other, different photos that you will try to export to the same folder.

Then, try the export of the different but identically named photos, to see what happens.

If the Photos App “clobbers” the different photos of the same names—completely without a warning of any kind—then I recommend you give Apple your Feedback on this matter. (Strong, but respectful, non-vulgar language would be appropriate.)

Fortunately, I don’t expect that outcome, but it’s best to test just in case, especially with your concern!

No, they don't overwrite the files. This is what you get when you export an original file 3 times to the same location: A sequential number in parentheses after each file name.

Welcome, Sebastian Kuhn, to Apple Support Communities!

You have been exporting photos from the Photos App, on your Mac (MacBook Air 13”?), to your drive.

Whenever you attempt to save a file with a name that matches another file, in the folder you are trying to save to, you should be greeted with a dialogue asking whether you want to Cancel the operation, Replace the old file of the same name, or to keep Both files.

The last option will append a number 2 to the end of the filename, or increment a trailing number, if the existing file ended in a number.

Unfortunately, when so many photo files end in numbers already, while this will prevent the new file from “clobbering” the old, it can lead to questions of which files are which.

However, you can use the file creation time to help sort this out.

(Personally, I tend to rename photos, in order to help me see what-is-what.)