MikeSeb

I really appreciate your help. I had figured out the necessary chmod command and parameters by the time you read the last post, and I have everything working. But I agree, a root-and-branch removal of the SynoCommunity package, and replacement with the DIY version, is my next step. Again, thanks for your help.

JimmyTheSaint, you are indeed that. I appreciate your help. I am able to login via ssh as "admin"; I have no idea what my "root" user password is; I don't recall being asked to set one up during initial configuration of the NAS, or at any time since. Looking at /etc/passwd in vi, the btsync user's line is already properly configured to end with /bin/sh. It's a good thing, because the file is read-only; I can't edit it. Not when logged in as root! Beyond that you've kinda lost me. I also don't know the btsync user's password; don't recall ever being asked to supply one on initial configuration. UPDATE: I managed to ssh into the NAS as root, and I got the latest version of btsync installed, thanks to this thread. The correct version number now shows when I access the btsync webUI to add folders, though in the "packages" section of the WebUI it still shows the old version. No matter. btsync seems to be running properly on my 412+. One problem solved. My remaining problem is that "don't have permission to write" issue that started this all off. Looking at the contents of my home directory where my folders are stored, the folders I'm able to write to with btsync have permissions drwxrwxrwx,while those I can't write to have permissions d---------. So how do I change this, if indeed this is the problem?

Ditching the community installation for a manual sounds like a good idea. I'm something of a command-line novice, so I admit to being intimidated a bit by that process! I made a stab at it but ran afoul of the NAS's root and btsync user passwords, which I didn't have when called for. Not sure I ever set either one up. I'm also not sure what you mean by "checking the owner" (of the files). At least through the Synology web management interface, I don't see anywhere that one can alter the owner, though you can exert granular control of all other permissions for a given file or folder. Any further advice would be welcomed. I have looked online for these answers fairly thoroughly, but the information is fragmented and a little tough to follow. Many thanks.

I have been running BitTorrent Sync 1.3.94 on a Synology 412+, installed via the SynoCommunity package, for some months without difficulty. With the synology as the central file repository, I've successfully kept files in sync between an always-on MacMini that runs Apple Mail and Hazel rules; and a MacBook Pro laptop, an iPhone, and an iPad. Everything has worked flawlessly until recently, and I can't figure out what has gone wrong. Suddenly I found I was having sync issues with a few of my more-used folders. I deleted them from sync and tried to re-add the folders thru the Synology BTS interface, only to receive the dreaded "you don't have permissions to write to the selected folder" error. I have checked and re-checked permissions on the folders in question, but I can't see any differences between how they're configured, and other folders that i've added in BTS on the synology and which work fine. I've tried adding test folders via the Shared Folder or File Station interfaces; doesn't seem to matter, still get the above error when I try to add them to BTS. Doesn't matter whether I access the Synology from my MacBook Pro or from the Mini; same error. I'm logging into the Synology over my LAN via a user account that has administrative privileges. This has to be a permissions issue of some sort, but for the life of me I can't figure out what changed, or where the problem lies. I've had to go back to Synology Cloud Station sync in the interim, but that is slow as Christmas. Any ideas would be welcomed as manna.