Ever since I did the Windows 10 Anniversary Update, I've been having issues mounting an external drive plugged into a Windows machine on my network.

My fstab:

//bowser.local/Fire  /media/Fire  cifs  auto,_netdev,comment=systemd.automount,sec=ntlm,uid=cameron,credentials=/root/.smbcredentials,iocharset=utf8,file_mode=0755,dir_mode=0755,defaults  0  0

I get the error:

mount error(5): Input/output error
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

I've searched around and tried a bunch of different options (my options didn't start that long!).

The thing is, it works fine with other shares. I tried sharing Desktop from the C drive on Windows just to test and it works fine, so I know it's not bad credentials or that it can't find the PC on the network or something... it appears to be something specific about the external drive? Well, drives... I have two I'm trying to mount and both have this same issue.

If I try the GUI and use "Connect to Server" in Nautilus to comment to smb://bowser.local, the Fire share shows up there, but if I click on it, I get the error:

Unhandled error message: Failed to mount Windows share: Invalid argument

The Desktop share works fine.

Don't know if it helps, but on my Mac, going to Shared > bowser > Fire in Finder works fine, too.

As mentioned, using Windows 10 with the Anniversary Update:

  • Windows 10 Enterprise 14393
  • Ubuntu 16.04 Desktop
  • Mac OS X 10.11.6

Update: Thanks to emk2203's comment, I got a new error trying to connect directly with smbclient: tree connect failed: NT_STATUS_INSUFF_SERVER_RESOURCES.

This led to more evidence that it was Windows' fault and a friend suggested I looked in logs. In the Windows logs, I found this error:

The server's configuration parameter "irpstacksize" is too small for the server to use a local device. Please increase the value of this parameter.

  • What do you get if you use smbclient to connect to the server? smbclient -L //bowser.local to list the available shares, if "Fire" is there, smbclient //bowser.local/Fire to connect. Do a ls within smbclient to see if the connection is valid.
    – emk2203
    Oct 12, 2016 at 14:24
  • @emk2203 So Fire is listed, but when I try to connect, I get this error: tree connect failed: NT_STATUS_INSUFF_SERVER_RESOURCES. That's at least a new error to explore! Edit: Connecting to Desktop (on C) works, just not Fire (an external drive).
    – CWSpear
    Oct 12, 2016 at 16:41

2 Answers 2


Thanks to the irpstacksize error I discovered in the Windows logs, I was able to find an article that talked about how to increase that value (putting the gist of it below in case the link breaks).

It's a registry entry (edit via regedit) (create it if it doesn't exist--it did not exist for me):

IRPStackSize DWORD 0x0000000f (15)

IRPStackSize is case sensitive. Decimal 15 is the default. They say to increase it to 5 until (50 is the max?). I couldn't find any evidence that increasing it to 50 would have any real negative consequences (and most people seemed to believe it won't), so after it still wasn't working at 33, I jumped to 50 and it worked!

In between each change you need to restart Services > Server for the change to take effect.


Moin, I had the same problem. After long search at google, I found the error by my self.

The Anniversary Update changed my network-firewall-state to public, so it blocks everything. After I changed it back to privat it was solved.

Greets from Berlin.

  • Unfortunately, I'm still set to private and file sharing is indeed enabled. Firewall wouldn't explain why C drive folders work, but not external drives. I appreciate your response, especially cuz it looked like you signed up for an account just to try and help! :-)
    – CWSpear
    Oct 11, 2016 at 7:16

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