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D.Sandlin, Network Administrator
Category: Networking
Satisfied Customers: 13125
Experience:  5 years as a Network Switching Systems Operator In the US ARMY (31F)
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My sierra 754s keeps resetting (rewriting) my XP S3 registry

Customer Question

My sierra 754s keeps resetting (rewriting) my XP S3 registry on every boot up to TCP parameters I am trying to use to tweak internet optimization! How do I prevent the device from doing this?
Submitted: 4 years ago.
Category: Networking
Expert:  A. Stevens replied 4 years ago.

My name is XXXXX XXXXX I'm here to help you with this issue.

I think the only way you could make this happen is if you adjust the permissions on the specific registry key so that only your user account (or another administrator on the local PC) have the ability to edit the key.

Please be extremely careful with this as it's risky, make sure you have a valid backup of your registry before adjusting the registry.

I would assume that the SYSTEM has some rights to that key, so if you remove the SYSTEM's right and only put your user account or some other admin account the application (or device) shouldn't be able to change it.

Please carefully try that, and please let me know if you have any questions.
Customer: replied 4 years ago.

OK, I have changed the permission for the SYSTEM "Deny" for the following keys that keep changing:

MaxGlobalTcpWindowSize, TcpWindowSize and MTU for the Sierra Device Interface key.

Expert:  A. Stevens replied 4 years ago.
Ok good, are you going to test?
Customer: replied 4 years ago.

I'll test it now and respond, I hope I have not screwed the registry up in the process.

Expert:  A. Stevens replied 4 years ago.
Ok, as long as you took a backup of the registry you should be fine.

You can also utilize System Restore to reset any changes you may have recently made.
Expert:  hongkongpom replied 4 years ago.

Hello and welcome to my name isCustomerXXXXX I'm here to help you with your networking question.


Rather than tweaking the registry yourself I recommend & use the free TCP Optimizer which will do all the settings for you.


You can download it here

Customer: replied 4 years ago.

I used SG TCPOtimizer. Already been there and done that.

DRESteve2000 told me to reset SYSTEM permission amd now I have the Black Screen of Death! The following message appears:


lsass Application Error

The application failed to initialize properly (0xc0000142)

Click OK to terminate the application.


Then nothing!

Expert:  hongkongpom replied 4 years ago.

Thank you for your reply


Sorry but you didn't mention that you had tried TCP Optimizer and I don't know why you're rating me bad service when I didn't give you the registry instruction.


If you are now getting a black screen of death and can't boot into Windows in order to do a system restore or registry restore then please press the f8 key when you boot up your computer and choose the "last known good" option and see if you can boot up.


Let me know how it goes.

Customer: replied 4 years ago.

I'm not rating you I'm rating DRESteve2000 with bad service.

Expert:  hongkongpom replied 4 years ago.

Thank you .


Sorry but the rating has appeared next to my entry. I'll alert Customer Service.


By the way have you been able to boot up please?

Customer: replied 4 years ago.

Not yet. I have a dupe copy of the hard drive I am responding to you now.

I am starting the Microsoft instructions on recovering the system from the recovery console.

Expert:  hongkongpom replied 4 years ago.

Thank you for your reply


Before you try the Recovery Console ...


If the f8 "last known good" is not working, you can launch System Restore this way:


When you press f8, choose safe mode with command prompt


1. Your computer will then boot to a command prompt (dos window). C:\....... you want to note what comes after the c:\ because you may need to change the default directory.


2. Change the directory by typing.

cd c:\windows\system32\restore\ Then press the Enter key.


3. Then press the Enter key.


4. Type: rstrui.exe



A couple of other things come to mind.


Are you using a D-Link network adapter?

If so, use the XP device manager to disable the "4X Mode" and see if that stops the MTU from being reset.


I assume when you change the MTU with TCP Optimizer you are selecting to change the correct adapter :-)...I only mention this because I made this mistake myself when I first used it.


Best regards,

Customer: replied 4 years ago.

Using TCP Optimizer and resetting the Rwin and GlobalMax Rwin

resets the TCP optimized values from 130560 130560 to 513960 513960 respectfully on reboot (always). There must be a way of keeping the device from resetting values!

Question unanswered!

Expert:  hongkongpom replied 4 years ago.

Hello there sorry about the delay in replying. We are in different time zones and I had problems with the Internet here in South Africa last night.


Did you see my answer above where I mention the D-Link network adapter?


You can check this out by typing devmgmt.msc in the "open" field of start>run

You will see the Device Manager open as shown in the image at the bottom of this answer.


Under the devices you will see your Network Adapters. If you expand the entry and you see that you indeed have a D-link adapter, then please double click the entry to show the properties. Look for the the 4x Mode option and disable it.


The issue lies in the driver for the adapter which stops the MTU from being change in order to facilitate a faster network data speed.


Customer: replied 4 years ago.

There is no D-link network adapter, only USB\HSPA_DEVICE\6&A081329&0&7&012701004639620, which is the Sierra754S 4g Air Card.


Question unanswered.

Expert:  D.Sandlin replied 4 years ago.
Welcome to JustAnswer..

My name is Dustin and I am a member of the expert community here..

Were you able to get the computer booting again? If so.

To avoid any potential conflict that might cause any more system instability..

In an effort to resolve this issue, I would like to offer you a remote support session.. What a remote support session does is allow me to connect to your and to your computer, and then I can manually see whats happening from here, and then make the neccessary changes while you observe. Our remote software that allows this one time connection is secure, and easy to use.

Would you consider remote support as a viable option to allow us to resolve your issue more expediciously and efficiently?
Customer: replied 4 years ago.

O.K. however I don't believe it will resolve the adapter problem.

Expert:  D.Sandlin replied 4 years ago.
Just so were clear..

By adapter problem you mean.. These registry values of MTU=1500, MaxGlobalTcpWindowSize=513920, TcpWindowSize=513920 for your adapter, resetting after every shutdown..

Customer: replied 4 years ago.


Customer: replied 4 years ago.

My window of resolution is closing since I am signed up for the 7 day free trial. We are going out of town early tomorrow and won't be back until the trial runs out. If you want to scan my system, do it now otherwise I shall call for a refund.

Expert:  D.Sandlin replied 4 years ago.
I personally am going to have to opt out at this time..

The stability of my router and internet connection hasnt allowed me to conduct the remote support sessions I would like to.. There was a large Stormcell that came through Northern Indiana, and Im going to have to replace my modem and router first thing in the morning.. So today wont work for me, as running off of a phone hotspot is not conducive to a strong connection for remote support.

I will opt out, and if no one else steps in to help you this evening, send a message and I can submit the refund request to customer service this evening on your behalf.

Customer: replied 4 years ago.

Yes, send the refund request. I appreciate your time.