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Check Windows 10 system files with System File Checker

I was thinking the other day about what program I use the most in doing computer repair. The one program I use the most on Windows based computers would have to be System File Checker (SFC). SFC checks for system files that may have gotten corrupt or replaced with incorrect versions. Here's how to check Windows 10 system files with System File Checker.

Check Windows 10 system files with System File Checker

SFC has been included in every version of Windows since Windows XP. In fact, you can also build it into the Microsoft Diagnostics and Recovery Toolset (DaRT). There is no shortcut or link to SFC in Windows 10, as it runs inside of an Administrative Command Prompt.

How to open a Command Prompt with Administrator privileges in Windows 10

SFC running inside of Windows 10 Administrative Command Prompt

The following is the syntax and switches for SFC. The most commonly used syntax / switch is: sfc /scannow.

SFC [/SCANNOW] [/VERIFYONLY] [/SCANFILE=<file>] [/VERIFYFILE=<file>] [/OFFWINDIR=<offline windows directory> /OFFBOOTDIR=<offline boot directory>]

/SCANNOW (Scans integrity of all protected system files and repairs files with problems when possible.)
/VERIFYONLY (Scans integrity of all protected system files. No repair operation is performed.)
/SCANFILE (Scans integrity of the referenced file, repairs file if problems are identified. Specify full path <file>.)
/VERIFYFILE (Verifies the integrity of the file with full path <file>. No repair operation is performed.)
/OFFBOOTDIR (For offline repair specify the location of the offline boot directory.)
/OFFWINDIR (For offline repair specify the location of the offline windows directory.)


sfc /scannow sfc /verifyfile=c:\windows\filetobereplaced.dll sfc /scanfile=d:\windows\filetobereplaced.dll /offbootdir=d:\ /offwindir=d:\windows sfc /verifyonly

Once SFC is done scanning the system files, it will give one of four possible results:

  • Windows Resource Protection did not find any integrity violations.
    All system file are fine and you're good to go.
  • Windows Resource Protection could not perform the requested operation.
    There may be another program preventing SFC from running. In this case boot the system up into safe mode and run SFC from there.
  • Windows Resource Protection found corrupt files and successfully repaired them.
    All system files are now correct and you're ready to go. If you want to view the repair details, see below.
  • Windows Resource Protection found corrupt files but was unable to fix some of them.
    If you get this message, SFC found a file or files that it wasn't able to repair. The next thing you will need to do is find out what the name of the file(s) are. Using the Find String utility, you can filter out the SFC results with only the components that were scanned and create a text file with that information on your Desktop called sfcdetails.txt. Just copy the following code into an Administrative Command Prompt:
findstr /c:"[SR]" %windir%\Logs\CBS\CBS.log >"%userprofile%\Desktop\sfcdetails.txt"

Manually replacing a corrupt system file in Windows 10

Note: To replace a corrupt system file, you will need to have a known good copy of the file(s) in question. A good source for files is another computer or virtual machine running Windows 10. Since I do computer repair for a living, I have all of the versions of Windows that are still supported by Microsoft running inside of Oracle VirtualBoxes.

First thing to do is make note of the location (path) and name of the file(s) that need to be replaced from the sfcdetails.txt file. Once you have another copy of the corrupt file(s), you will need take administrative ownership of the file(s). To do this, modify the following command with the path\filename of the file you want to replace and then type it into an Administrative Command Prompt:

takeown /f path\filename

Example: takeown /f C:\Windows\FileToBeReplaced.dll

Next you will have to grant administrators full access to file(s) being replaced. To do this, modify the following command with the path\filename of the file you want to replace and then type it into an Administrative Command Prompt:

icacls path\filename /grant administrators:F

Example: icacls C:\Windows\FileToBeReplaced.dll /grant administrators:F

Third thing to do is copy over the new file(s) and replace the corrupt one(s).To do this, modify the following command with the path\filename of the file you want to replace and then type it into an Administrative Command Prompt:

copy path\filename path\filename

Example: copy C:\Temp\FileToBeReplaced.dll C:\Windows\FileToBeReplaced.dll

Maintain your hard drive with SpinRite

When it comes to maintaining a hard drive, running a disk check will usually find any software related issues. But when I need to check the hardware inside of a hard drive, I will use SpinRite from Gibson Research Corporation.

Intro screen from GRC SpinRite
Intro screen from GRC SpinRite

SpinRite is a magnetic storage data recovery, repair and maintenance program and works only on HDD's (Hard Disk Drive) and not SSD's (Solid State Drive). SpinRite includes a feature called DynaStat that can reassemble missing data from bad sectors. SpinRite is a self-contained program that runs on top of a version of FreeDOS (Free Disk Operating System).

Graphic Status Display screen from GRC SpinRite
Graphic Status Display screen from GRC SpinRite

SpinRite has five (5) levels of operation, each building on the previous level.

  1. Examine the hard drive surface. This level will read every sector of the selected partition(s) psychical surface looking for areas that appear to be healthily but could possibly fail in the future.
  2. Recover unreadable data on drive. This level will read every sector of the selected partition(s) psychical surface looking for unreadable data. Spinrite will then attempt to recover unreadable partition data using the built-in advanced recovery technology.
  3. Refresh the hard drive surface. This level will read and write every sector of the selected partition(s) psychical surface, essentially exercising the hard drive. It basically test and verifies every sector on the partition(s).
  4. Locates surface defects. This level will read, write and invert every sector twice of the selected partition(s) psychical surface. This tests and verifies that every 'bit' on the selected partition can be successfully written to and retrieved.
  5. Restore known good sectors. This level does everything that all of the other levels do and restores any areas that may have been previously mark as defective, but now are found to be reliable.

DynaStat Data Recovery screen from GRC SpinRite
DynaStat Data Recovery screen from GRC SpinRite

To run SpinRite you will need to create a bootable media, either a CD or USB drive. Normally, if your computer is running Windows XP, Windows Vista or Windows 7, all you have to do is insert the bootable media and restart your computer. If your computer doesn't boot up to the SpinRite media, you may have to change the boot order in the system BIOS (Basic Input/Output System).

If your computer has Windows 8, Windows 8.1 or Windows 10, more than likely your computer has UEFI (Unified Extensible Firmware Interface) enabled BIOS. To run Spinrite on one of these systems, you defiantly have to go into the BIOS and turn off the UEFI boot functions temporality.

Now, if in either scenario SpinRite doesn't recognized your hard drive, you may have to also change the drive mode in the BIOS from AHCI (Advanced Host Controller Interface) to ATA (AT Attachment) temporarily.

SpinRite is available from Gibson Research Corporation for $89 (as of this writing). For more information on SpinRite, just follow the link below.

Gibson Research Corporation SpinRite

How to replace a CD/DVD/BD drive in your desktop computer

When it comes to desktop computer repair, one of the most common hardware failures are CD/DVD/BD drives. If you're having problems with getting the disk tray to eject or disks are not being recognized, it may be time to replace it. Here's how to replace a CD/DVD/BD drive in your desktop computer.

How to replace a CD/DVD/BD drive in your desktop computer

So you're tired of trying to get your old desktop CD/DVD/BD drive to work and are ready to replace it with a new one. Having to use a paper clip to manually eject your computer's CD/DVD/BD drive tray can get old really quick. Replacing a desktop CD/DVD/BD drive is fairly easy; you just have to make sure you get one with the correct connections and dimensions.

Find a new drive

The majority of CD/DVD/BD drives on the market nowadays will have SATA (Serial ATA) connectors for data and power. But there are still quite a few older systems that still use PATA (Parallel ATA) for data and 4 Pin Molex for power. SATA type drives are the de facto standard, so finding PATA replacement drives can be tricky. Newegg and TigerDirect are good places to find these older style drives.

SATA and PATA drive connections
PATA and SATA drive connections

Desktop CD/DVD drives have standard width and height dimensions, so all you have to do is check the depth of your existing drive. Sometimes you have room to put a deeper drive in and sometimes you don't. Always check to see what kind of space you have available before purchasing a replacement drive.

Uninstall the old software

Once you have your new CD/DVD/BD drive you will need to uninstall the software that came with your old CD/DVD/BD drive. It's usually a version of Nero or PowerDVD and it is branded to your old drive. Once you remove the old drive, the software that came bundled with it won't work anymore. Your new drive should have come with its own disk burning software.

Install the new drive

From here we need to turn the computer off, disconnect the power cord from the back of the system and open up the case. Now there are two possible ways of mounting the CD/DVD/BD drive in the case: screws or quick release rails. You may have to remove the front bezel from the case to get the CD/DVD/BD drive, as it will need to come out the front of the case. Make note of the connections and remove the old drive and replace with the new one.

Drives attached by screws and quick release rails
Drives attached by screws and quick release rails

Install the new software

Once you get the system back together, power it up and let Windows discover the new CD/DVD/BD drive. Windows may require a restart to finalize the setup. After that you are ready to install the software that came with the new drive.

The most common computer video display connectors

When it comes to computer repair, you have to be prepared to work on different types of systems. One of the biggest issues is having the correct video display connector. With more than ten different types of connectors it can be difficult to identify the correct one. Here is a list of the most common video display connectors.

What type of video connector do you have?

Most common video display connectors  
3 variations - 4, 7 or 9 pins.
S-Video display connector
VGA (Video Graphics Array)
2 variations - DE-9 (9-pin) & DE-15 (15-pin).
VGA display connector
DMS-59 (Dual Monitor Solution, 59 pins)
It provides two DVI or VGA outputs in a single connector. An adapter cable is needed for conversion from DMS-59 (digital) to DVI (digital) or VGA (analog).
DMS-59 display connector
DVI (Digital Visual Interface)
5 variations - DVI-I (Single Link), DVI-I (Dual Link), DVI-D (Single Link), DVI-D (Dual Link) & DVI-A .
  • DVI-I (integrated, combines digital and analog in the same connector; digital may be single or dual link).
  • DVI-D (digital only, single link or dual link).
  • DVI-A (analog only).
DVI display connector
HDMI (High-Definition Multimedia Interface)
Electrically compatible with the DVI.
HDMI display connector
Backward compatible with VGA and DVI through the use of adapters.
DisplayPort display connector

My digital toolbox

Every computer repair technician has a digital toolbox, more than likely several. They are either on a CD / DVD or USB drive and contain programs that we use on a regular basis. Here are a few of the programs that I have in my digital toolbox.

My Digital Toolbox

All of the following programs have one thing in common, they don't require installation. Just right-click on them in File Explorer and select Run as administrator, that's it. Some of the programs may require access to the Internet for complete functionality.


One of the best stand-alone adware removal tools I have found yet. Right out of the box and it will scan your system with a generic set of definitions. But if you are connected to the Internet before you start up AdwCleaner, it will download a current set of definitions. And if you select uninstall, it will remove any quarantined files and then delete itself.


.NET Framework Cleanup Tool

When it comes to resolving .NET problems, sometimes you're better off just removing and reinstalling the framework. The .NET Framework Cleanup Tool is a stand-alone program that does just what its name implies. Just pick the version you wish to remove (or all) and click Cleanup Now. Once it is complete, just reboot and use Windows Update to reinstall whatever version of .net framework you need.

.NET Framework Cleanup Tool

Sysinternals Suite

Hands down the best collection of Windows trouble shooting tools. All of them are stand-alone programs, over 70 altogether. From seeing everything that automatically starts up with Autoruns, exploring running processes with Process Explorer or monitoring network usage with TCPView. When it comes to Windows diagnostics, the Sysinternals Suite cannot be beat.

Sysinternals Suite

Customer service is #1

Here at Geeks in Phoenix, we take pride in providing excellent customer service. From computer repair, virus removal and data recovery, we aim to give the highest quality of service.

Bring your computer to us and save

Our in-shop computer repair service  is based on the time we work on your computer, not the time it takes your computer to work!

Contact us

Geeks in Phoenix
4722 East Monte Vista Road
Phoenix, Arizona 85008
(602) 795-1111

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Geeks in Phoenix is an IT consulting company specializing in all aspects of Computer Repair / PC Repair / Laptop Repair. Since 2008, our expert computer repair technicians have been providing outstanding Computer Repair, Virus Removal, Data Recovery, Photo Manipulation and Website Support.

Geeks in Phoenix have the best computer repair technicians providing computer repair and service in Phoenix, Scottsdale and Tempe Arizona. We offer In-Shop, On-Site and Remote (with stable Internet connection) computer repair service.

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