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VMware File Extensions

VMware File Extensions Explained

VMware File Extensions Explained

VMware File Extensions are specific virtual machine files and extensions that created for each Virtual machine in VMware. Understanding these files and usage of these extensions helps us while performing day to day tasks with VMware products. The following image gives us a good understanding of these extension.

VMware File Extensions


Let’s take a look at each of these extensions and their functionalities.

.VMDKIt is the actual virtual hard disk files of the virtual machine. It is the biggest file in virtual machine folder. Additionally, if we have chosen 2GB split of .VMDK files, the number of .VMDK files depends on the size of the virtual disk.
.NVRAMIt is the BIOS of the virtual machine.
.VMX It is the configuration file of the virtual machine. We can open and change it through text editor.
.HLOGThis file is created when the VM is VMotioned.
.LOGAs the name suggests, it is the Logs file for the VM  that can be used for troubleshooting.
.VMEMThis is the paging file of the VM. Moreover, if the VM is running this file exists and it is deleted as soon the machine is powered off, except when we take the snapshot of the VM.
.VMSSIt is the newer version of .STD file. When/If we suspend the VM, this file stores the suspended state of the VM.
VMSDIt stores the metadata of the snapshot.
.VMSNIt stores the running state of the VM since the VMDK at the point of snapshot and the changes made till now.
.VMTMThis file contains the team membership details and the VM’s that are actively participating in the Team.
.VMXFIt holds the teaming information for the VM. if the VM is or was part of a team. We can open this file with the text editor.


Finally, if you want further details you can check the VMware documentation, “What files make up a Virtual Machine”

re register vss writers

Re Register VSS Writers In Windows

Re Register VSS Writers

“Re Register VSS” writers is the process that brings the unstable writers back to stable state. VSS writers are very important because they are used by backup applications to take the backup. For example, Microsoft Exchange has its own VSS Writer called “Microsoft Exchange Writer”. These writers should be in the “Stable ” state for the backups to be completed successfully.

We can check the status of the writers by running the following command on CMD:

VSSAdmin List Writers

The result looks like this:

vssadmin list writers

Some times the writers become unstable or hang, as a result the backup fails. A simple server restart usually brings them back to the stable state as a result the backup starts working again. But some times the writers do not come back to the stable state. In those situations, we have to re register the volume shadow copy service Dll’s.


The method is same in Server 2008, 2008 R2, 2012, 2012 R2 and Server 2016. The steps are as follows:

First of all, open CMD and go to the “%WinDir%system32” directory

Secondly, run Net Stop VSS and Net Stop SWPRV to stop the volume shadow and MS Software shadow copy provider services.

Stop Services

Next run the following commands one by one to re register the dlls and services.

regsvr32 /s ole32.dll
regsvr32 /s oleaut32.dll
regsvr32 /s vss_ps.dll
vssvc /register
regsvr32 /s /i swprv.dll
regsvr32 /s /i eventcls.dll
regsvr32 /s es.dll
regsvr32 /s stdprov.dll
regsvr32 /s vssui.dll
regsvr32 /s msxml.dll
regsvr32 /s msxml3.dll
regsvr32 /s msxml4.dll
vssvc /register
re register vss writers

Finally, run “Net Start SWPRV” and “Net Start VSS” to start the MS software shadow copy provider and volume shadow services.

Check the writers again by running “VSSAdmin List Writers”, and hopefully this time the writers will be in stable state and most importantly the backups will also complete.


For further reading, “Volume Shadow Copy Service”.


Automatically detect settings

Downloading Proxy Script in Google Chrome

Downloading Proxy Script in Google Chrome

At time you may see “Downloading Proxy Script” in the lower left corner of chrome window in google chrome and the websites taking forever to load. This problem is faced when you are using a proxy server to access the internet. Companies use proxy server to control the internet access for their employees. While users put the proxy in their Internet Explorer Proxy options. Google chrome uses these proxy settings from internet explorer to reach the internet.


The solution to “Downloading Proxy Script” problem is pretty simple. You just need to uncheck the “Automatically Detect Settings” in the proxy settings.

First of all, In Google Chrome go to settings and look for “Proxy settings”. Alternatively you can open the Internet Options in Internet Explorer. Because both open the same window.

Automatically detect settings

On the connections Tab, click “Land Settings” and UNCHECK “Automatically Detect Settings”, click OK.

Finally, close the chrome and open it again, now Google chrome will load the sites faster without showing the “Downloading Proxy Script”.


If you want to know more about Proxy settings in internet explorer you can read Technet article about “How to configure Internet explorer to use proxy server”