Finder Error 36

[jw3571]

When trying to move my photos library over to an external I got an error message that said finder can't complete he operation because some date "photos" library can't read or written. Error code 36. When i back up using time machine i don't get an error messages. I've been trying to clear some space so that's why i trying to move it to a new external.

Two questions, is there anything i can do fix this? If i decided to buy a iMac, would I run into this same error when i move everything from my old machine to my new machine?

 

[organicCPU]

IMO, it's best to make a complete backup first to a proper functioning drive with something else than Time Machine, e.g. Carbon Copy Cloner or Super Duper as fast as possible, as it could be a dying drive in your case.

If you do have a backup ready you can start to find the reason or solution for your Error -36.

I ran into that error once while trying to retrieve files back from a Time Machine backup right after an OS upgrade many years ago.
Your situation can be completely different, but I managed to get files back with following commands, but not by Finder drag'n drop or Time Machine itself.

cp -Ri /source/folder /destination/folder
or
rsync -av /source/folder /destination/folder

It turned out that the internal drive really died completely without any unusual SMART status message around one year later. What I've been observing quite a few times, is that usual HDD drives tend to work approximately 5 years (+/-5 years).

Maybe, after backing up your system you should also read this thread up to the final post: https://discussions.apple.com/thread/2271520

Concerning your second question: Worst case is that a new iMac won't prevent your old Mac's drive from dying...yes it's possible to get the same error.