Losing mapped drives:" the local device name is already in use" Sonicwall Global VPN Client

Thanks for your suggestion.

When I say enable/disable, I'm talking about the Sonicwall client software.  When I click "disable", my VPN connection disconnects, then "enable" re-connects.   The mapped drives and exchange are getting disconnected even when Sonicwall VPN client is still showing "connected".

Either way, I will try your suggestion once I remember what our ip is.

Thanks.  This is all pretty foreign to me, but I'll give it a try.  Would this be causing the disconnected network drives as well?

FYI, I tried mapping by ip and the problem remained.

I'm now trying mtu at 1300 and will update.

Using Dr TCP to change to 1300 made no difference.  I did restart after changing settings, which Dr TCP download page said to do.  I didn't take time to experiment with how low, just went to 1300. ..

Did you check all your timeout (including idle timeout) settings? As a thought, but only after testing-  have you tested this laptop from other locations, including wifi hotspots? If no issues from other locations, it could be your router.

As far as the mtu issues, did you slowly drop down to say 1440? You gradually drop down in small increments.

I didn't slowly drop down, just tried the lowest mentioned setting (1300); thought I could short-cut.   Checking from another location is a good suggestion, which I will try, thanks.  

I'm slow about responding, but please know that I am still interested and appreciative of everyone's input.

Just keep us posted and we will help you solve this.  MTU settings need to be gradually dropped down until you find the right setting.

Really, I haven't abandoned this question.  I had to give the laptop to another user and haven't been able to work on it.  Would it be better to give points for the likely solutions and let it close?

Again, I'm appreciative of everyone's assistance.

I actually got to work on this today (what else do you do on Easter?

Being very inexperienced at using the command line, I had trouble trying bignewf's suggestions.  However, I did get DrTCP and used another tool from the same site - the "online tweak tester" at http://www.dslreports.com/tweaks.  I did as the "tweak" suggested and changed RWIN to 40,000.  Just for the heck of it, I then tested the VPN connection and it seems to be working properly.  

It's a little unsatisfying to not understand exactly what I did or how it helped, but if it works I won't complain!

Just for my info,

Why would I get "the following command was not found: interface ipv4 show interface " when trying to do:
netsh interface ipv4 show interfaces?

How do I enter the vertical bar in the following command, and can I enter the remote host name instead (either remote.domain.com or just domain.com)?
ping -l   1500  [ip address of remote host] -f

Thanks very much for your help so far!  I'll report back whether it really works.

I was trying to follow the instructions in the post above (2/17/2010), but could not figure out the following:
ping -l   1500  [ip address of remote host] -f

What are the two characters after the word "ping".  How can I enter them?  Am I missing something?  I don't mind looking foolish if I can learn something and maybe others can learn from my silly questions.

emjoyce,

type

   ping /?

at a command prompt to get the syntax of the ping command.  This is true for most commands, e.g.
dir /?
sort /?

In fact you can type

help ping

and that just calls "ping /?"

-l (as in lowercase L) is the "send buffer size"

-f is "Set don't fragment flag in packet"

Thank you,  For some reason I didn't believe it was a lowercase l.

Once I get a report from the user, I will hopefully accept a solution and close this.

I think several good troubleshooting tips were given, but since the OP appears to have abandoned the question, who knows if it helped solve it or not.

I haven't really abandoned.  It's just that the person I am helping can't part with her laptop long enough for me to try things out.  It seemed to be solved (see my post 4/4), but then she reported that it wasn't working again and I haven't been able to get it back to try anything else.  I will close the question, and award points for helpful suggestions that probably solved it or at least helped.  Thanks.