Smb file transfers between mac (sequoia 15) and synology NAS not working well

Have Synology DS1522+. No issues prior > mount drives on mac > transfer files from one drive on NAS to another drive on same NAS. i.e. using finder to manage files/folders on Synology NAS. With release of Sequoia (OS 15) > with any file movement larger than 2gb will get error 100035 or 51 and the drives will un-mount. Scrubbed system and went back to version OS 14 > no issues. Reinstalled OS 15.2 > same issues are back (problems with smb). From reading - a lot have this same problem. What is not known is if it’s a problem created by Apple or Synology. Speculation that Apple using current SMB while Synology is several versions behind. Writing this to see if anyone has been able to pin down where the problem is (what’s causing the issue?).

I can’t answer any Mac-Sequoia issues but I have to ask, why would you choose copy from drive to drive via the Mac instead of directly on the NAS? Any disk-to-disk transfer will be much quicker if it doesn’t have to go over the network.

right - i’ve gone to dong that (web based - Synology File Station). I’ve got 5 drives on my NAS - and each one has specific items. One drive is used as main source for input - then i move content to other drives. And it’s all just way more convenient to do it thru Finder - as i’ve got all my shortcuts setup etc. Point is… that it used to work just fine - now it doesn’t - and related to Sequoia (and it’s interaction with Synology).

Got in touch with Synology. They were awesome in their response. Had me change - in Advanced Settings under SMB - the protocols from SMB3 to SMB2. And that restored functional ability of my mac integrating with my synology NAS.

Hi, thank you for sharing. We all learn from that.

The default is currently minimum SMB2 and maximum SM3. Is this what Synology advised? What where your previous settings if I may ask?

I had both of the protocols set to SMB3 > which i then changed (both) to SMB2.
Still working well. Did notice Synology put out update 3 just now (Feb 8/9) - but didn’t see any mention of SMB with the info.

Thank you for the feedback. I assume that SMB2 is still needed. The default (min. SMB2, max. SMB3) would work as well.

A recent update, DSM 7.2.2 Update 3, is about a security fix—no changes related to SMB.