File sharing broken on Mojave

I was having the same issues. Got with support and they suggested a Fresh install of the operating system, due to the problem occurring directly after the update. I am accessing Mac Mini machines via screen share. I needed to connect a screen and Keyboard in order to Restart the machine with the command/option/R from the keyboard. Seems to be working so far. I will update if it does not hold

We did fresh install, upgraded, downgraded, everything, seemed that mac os server downgrade to 5.7 stopped smb sharing collapsing. But in the end it didn't, at least 4 , 5 reboots a day where necessary to keep smb filesharing up. Some of the shares where APFS shares. We moved around a lot of data (+ 50 TB) en converted the shares back to HFS+. Replaced a few windows laptops and are back on AFP sharing only which works flawless, much snappier and no crashes. Looks like Apple SMB (x?) implementation is nice for at home with 3 computers or so but absolutely useless in office with +20 / 30 people. And let's not forget removing setting ACL in Mac OS server without notice... pffff. Preparing 2 mac-mini's now to be linux server, with Samba AD ...... because Apple server is a dead-end street.

Have you tried checking the WiFi connection to see if both computers are on the same WiFi network?

I am not sure this is the same problem others are seeing, but I just went through a similar connection problem after migrating to a new MacMini running 10.14.5. It could not find my MacBookAir running 10.13.6, and the Air couldn't find the Mini. I noted that some sharing options had not been turned on for the Mini, and doing that let it find my wife's MacBook running ElCapitan (10.11.6), but not the Air. I restarted the Air, but that didn't solve the problem. Then I looked at the WiFi connection and realized that the Air had picked up an open WiFi connection at a neighbor's house instead of the WiFi on my secured Verizon FiOS line. Switching to the same WiFi as the Mini and the old MacBook solved the problem. Note that it may matter if your WiFi has separate 2.5 and 5.0 GHz networks.

This is a problem that I first noticed with High Sierra, although it could have existed earlier. I find the WiFi connection can shift if you move between rooms and hit a dead zone. It also can shift if the WiFi power goes out but a laptop is still running. You can reduce the problem by going to the Network Control panel, picking the Advanced Setting, and arranging WiFi connections in a preferred order.

Got the same problem here as well... Sometimes the finder crashes and all apps that have a file on my shared volume open. Afterwards I cant reconnect unless i restart the connected server (or just toggle it's file sharing preferences)

Updating Status: Seems we needed to reboot several times this morning the issue is recurring. Lasted 7 days and 3 of those were with no activity. We are on Gig Cisco switches, direct connect with the clients (no Wi-Fi) I have reset, Re-Installed, and I cannot keep a solid file server (sharing) connection. Is Apple going to not patch this and wait to introduce a new system? LITTLE HELP HERE PLEASE

Having very similar issues as others.

I have a 2018 MacBook Air purchased Dec of last year and a 2018 Mac Mini (I use my Mini as a "server" - never gets turned off; set to stay awake) purchased mid May of this year.

My Air came with High Sierra but was upgraded to Mojave during initial setup. My Mini may have been the same but I don't recall (It may have came with Mojave).

Even before I got the Mini I would have minor issues with file sharing (I've only ever used SMB) on my Air. Sometimes I would try to connect to a given share on my Synology NAS units (I have 2) and it would timeout but as soon as I tried it again it would work. Sometimes I would eject a share and immediately reconnect to it in order to get new files/folders to appear immediately rather than later.

Anyway, the "real" issues didn't start until I got my Mini. After some time (I've gone as long as a month without issues and as short as a few days) I will be unable (it will timeout) to connect to shares (via alias, Connect to Server, Finder Locations (Networks & individual hosts)) on the Mini from the Air but the Mini is able to connect to the Air. During this time both my Air and Mini can connect to shares on either of my Synology units. I tried enabling AFP (on the Mini just for troubleshooting) for the first time the last couple of times this issue occurred but AFP doesn't work either (although with AFP I at least get prompted for credentials but they don't seem to work (the login box just bounces). Restarting either mac doesn't seem to help - it just seems to start working again when it feels like it (hours to days later).

I last had this issue several hours ago and as of typing this it is still now working. In the past I have also had Finder crash on me but so far not this time.

Some updates : after a long time with no issue after doing the trick of SMB to AFP to SMB only, some days were continuously dropping the share with freezes from the clients. Since it is work environnement with 10 clients, I moved the shared files on an external drive formatted HFS+ with AFP only (didn't try SMB since no windows connected). No drop so far for more than 2 weeks. Thank you Apple for the forced investment and time loss !

I'm holding on 10.14.3

Using TinkerTool Server App to maintain share permissions.

Having to reboot every 2 weeks or so ... memory overflow?!

Mojave 10.14.6 seems an age in coming

They are either having issues ro waiting for Catalan to start us all over again on this path of serious issues?

#angsty? yes, it's as bad as a 20 year Adobe Illustrator issue :-O

Update - We're still on Mojave 10.14.5 on a 2018 Mac Mini and still have some problems but it is much better. The trick for us was to go to an external hard drive formatted as HFS+ and connect via afp. We still have some Windows machines that have to connect smb but that seems to work pretty well most of the time. We had to restart the server yesterday to get file sharing working again but that was the first time in a week so not too bad.

From what I can tell, the problem for us was using SSDs formatted as APFS. Didn't matter whether we connected afp or smb, the shares failed after a few hours or less. So it seems like sharing a drive that is HFS+ has made the most difference for us and is working much better. I don't even know if you can format an SSD as HFS+ anymore and then maybe you could share an SSD without many problems. I'm not willing to try it at this point though since our system is working.

So I'm just saying that it seems like the problem is more with APFS formatted drives than with smb; at least for us.

I guess I logged in from a different Apple ID this time to post my answer!

So I gave an update right above this post as scottfromcrosby; to see my previous posts looks for the posts from murffturf and that will give you the details on other things we tried in case you need the detail.

I went back to 10.13.6 on my iMac (which is the server for 25 Mac-Clients). It still runs APFS, but eversince I downgraded from 10.14.5 everything works smooth as ever. APFS does not seem to be the matter in my case; SMB sure was...

Hope for a fix soon!!!

BTW: Clients still run on 10.14.5 and work like a charme! It only seems to get messy, when the server/file-sharer runs 10.14.5...

Just got off the phone with apple support and the guy I talked to said this is a known issue and 10.14.6 should fix it. Funny, the last 2-3 people I talked to at apple never mentioned this and had me jumping through all kinds to troubleshooting hoops.

iMac: Mojave 10.14.5 file sharing enabled with SMB only

MacBook Air: High Sierra 10.13.6; file sharing off

I can connect from Air to iMac and read or modify files on iMac.

But after taking the Air away on travel, upon returning connecting won't work without restarting the Air.

I have 9 clients accessing the smb server. It's working pretty well now on 10.14.6. I did have it lock up one time last week and had to restart the server but that was the first time in a couple of weeks. On 10.14.5 we were having to restart multiple times per day.

I think most of us figured that out and just went with SMB; the problem was that on 10.14.5 even SMB sharing was not stable. My problems have mostly gone away on 10.14.6 though so it seems like they addressed the issue.