Windows 7, Vista, or XP- Save the zip file to a location of your choosing. Once you have the zip file downloaded, open the zip file (Windows built in zipping program). Copy the folder inside to a new folder. It will unzip the contents, (This is the folder you will need when you are doing the steps below). You can also use the Extract All Files button (on the left under Folder Tasks, under File, Extract All). It will then ask where you want to save the file too. I recommend just putting a backslash ( ) at the end of the location already on the screen.

WinZip- Use the Extract button. It will ask you where you want to save the extracted files to, I recommend your desktop. Click the desktop icon on the left. Push the little yellow folder in the upper right corner of this active window. It will prompt you for a name for the folder (type in CAC Driver). Hit OK, then select Extract (lower right corner of this window). You should now see your new folder on your desktop to open up. Keep this for a later step.

Updating the Driver - Example is for an SCR-331

Windows 7, 8, & Vista - Right Click Computer, Select Properties

Click the Device Manager link (on the left side of your screen)

Select the triangle next to Smart Card Readers

Right click the SCRx31 USB Reader, select Update Driver software

Browse my computer... Select Browse, then desktop (or wherever you made the folder)

NOTE: One person had to select 'Search automatically for updated driver software' (This is very rare)

Select the folder (if using the firmware update driver below, stop at the driver folder, do not 'dig' down to AND or Intel folders) and then OK. Next

Your driver will be installed.

Windows XP - Right Click on My Computer, Select Properties,

Go to the Hardware tab, Select Device Manager,

Select the + next to Smart card readers.

Right click on SCR33x USB Smart Card Reader.

Select Update Driver, then No, not at this time, Next,

Select Install from a list or specific location (Advanced), Next, Unselect Search removable...,

Select Include this location in the search:, now hit Browse, find the folder we made a few moments ago.

All you have to do is select the folder and hit OK, Next, It should do the rest on its own. Select Finish when complete.

Updating the Driver - for IOGear GSR-202 reader

Plug your IOGEAR CAC reader into an available USB port
Allow Windows to load the generic driver
Go to the IOGear website and download the driver for GSR 202 CAC Reader to your desktop
Create a folder on the desktop to extract the driver's zipped files
Unzip the file to the folder you've created
Go to Device Manager
Select the CAC reader
Right click the driver
Select properties
Select update driver
Select Browse
Select the IOGear driver from the desktop folder. This is the unzipped IOGEAR folder
The driver gives you two choices: 32 bit and 64 bit. (this must match your version of Windows)
Install the driver
Insert your CAC into the CAC reader
The yellow light on the CAC reader should blink rather than remain a solid yellow
If the yellow light blinks on the CAC reader, then the computer has added the smart card as a device and the card will work properly

FIRMWARE UPDATE for SCR-331 Reader
(Requires a physical Windows computer, Mac using Bootcamp, or LPS (see next sentence below). It will NOT work in virtual Windows (examples: VMware, Parallels, or Virtual box)).
Intel based Macs can update the firmware using LPS (instructions on top of PDF page 37 (document page 34)) Video instructions
The firmware update 'should' fix the following problems:

A. Card reader is not recognized

B. Shows up as 'STCII Smart Card Reader'

C. Shows up as 'USB Smart Card Reader' (not necessarily a problem)

D. Does not read your 'Gemalto TOP DL GX4 144', 'Oberthur ID One 128 v5.5 Dual' CAC.

E. Does not read your CAC when using your Mac

F. Trying to use the Windows 7 built in Smart Card service instead of ActivClient.

NOTE: We are hearing more and more Mac users having problems with the SCR-331 reader. A recommendation is to get a Mac compatible reader.

Installation Instructions:
1. Download update file from MilitaryCAC or Identive
2. Unzip the downloaded file (by Right-clicking and selecting Extract All)
3. Update the driver present in the 'driver' folder (by following guidance above)
4. Once the driver is updated, Run FWUPDATE.EXE (lightning bolt) in the 'app' folder to update the firmware. Select the default choices.
5. Close all programs, restart your computer
NOTE: If you computer fails to recognize the CAC reader driver, you may need to try a different computer to do the update.
Now your SCR-331 reader can be used with Windows 8, 7, Vista or Mac.
FIRMWARE UPDATE for SCR-3310 reader
(V1 ONLY (doesn't have V2 after SCR-3310 on the label))
(Requires a physical Windows computer, Mac using Bootcamp, or LPS (see next sentence below). It will NOT work in virtual Windows (examples: VMware, Parallels, or Virtual box)).
Intel based Macs can update the firmware using LPS (instructions on PDF page 37 (document page 34)) Video instructions
NOTE: DO NOT use this update on a V2 reader. There is no firmware update for a V2 because it is already updated.
Click on FWUpdate.exe, this will update your firmware to version 5.26
CHECK SERVICES to make sure Smart Card is running
(This Video shows a very basic version on how to start the service)
If your CAC reader is still not seen by ActivClient, make sure that the Smart Card service is running.
Here's how: Go to: Start, Run (in XP), Start Search (in Vista), Search programs and files (in Windows 7), Right click Windows 'start button' select Run (Windows 8.1), type: Services.msc Scroll down to Smart card, double click it and set it to automatic and click Start
If you are unable to start the service; It doesn't show up; ActivClient still says no reader attached; or it acknowledges you have a CAC in the reader (but you can't access it) follow these registry edits below.
Windows 8 & 8.1
Automated method (double click the .reg file inside the .zip folder)
Windows 7 & Vista
Automated method (double click the .reg file inside the .zip folder) from MilitaryCAC
Automated method (with instructions) from Lazybit
Manual method for Windows 7 & Vista systems (mirror your registry settings to the PDF links below for your specific version of Windows).
Windows XP
Automated method (double click the .reg file inside the .zip folder)
Alternate cure for XP (Requires your original XP installation CD)
Anytime you make changes to the Registry it is a recommended you back it up first
If ActivClient still does not see the CAC reader, try these ideas (if they don't work, your only other option is reloading Windows onto your computer).

6 'high level' steps needed, follow down the page to make this a painless systematic process

Step 1: Your CAC reader must be Mac friendly
Visit the USB Readers page to verify the CAC reader you have is Mac friendly
'Some, not all' CAC readers may need to have a small program installed to make it work.
NOTE: Readers such as: SCR-331, GSR-202, GSR-202V, & GSR-203 could need firmware updates (NO OTHER Readers need firmware updates).
Information about these readers are in Step 2
Step 2: The Mac must be able to 'see' the reader

Plug the CAC reader into an available USB port before proceeding, give it a few moments to install

Step 2a: Click the Apple Icon in the upper left corner of the desktop, select 'About This Mac'
Step 2b: Click the 'More Info' (button)
Step 2c: Click 'System Report...' (button) (Only available in 10.7.x and above; 10.6.x and earlier will not see this window)
Step 2d: Make sure the CAC reader shows in Hardware, USB, under USB Device Tree (See image below). Different readers will show differently, most readers have no problem in this step. See Step 2d1 for specific reader issues.
Step 2d1: Verify firmware version on your SCR-331 or GSR-202, 202V, or 203 CAC reader. If you have a reader other than these 4, GO TO STEP 3
Step 2d1a-SCR-331 reader
If your reader does not look this this, go to the next step.
Below 'Hardware' click 'USB.' On the right side of the screen under 'USB Device Tree' the window will display all hardware plugged into the USB ports on your Mac. Look for “SCRx31 USB Smart Card Reader.” If the Smart Card reader is present, look at 'Version' in the lower right corner of this box: If you have a number below 5.18, you need to update your firmware to 5.25. If you are already at 5.18 or 5.25, your reader is installed on your system, and no further hardware changes are required. You can now Quit System Profiler and continue to Step 3.
Step 2d1b-IOGear GSR-202, 202V, and 203 readers
If your reader does not look like these, go toStep 3.
Below 'Hardware' click 'USB.' On the right side of the screen under 'USB Device Tree' the window will display all hardware plugged into the USB ports on your Mac. You should see “EMV Smartcard Reader.” If the Smart Card Reader is present look for 'Product ID' in the lower right corner of this box: If you see: 0x9540, you need to downgrade the firmware to 0x9520. If you see 0x9520, your reader is installed on your system, and no further hardware changes are required. You can now Quit System Profiler and continue to Step 3.
Step 3: Verify which version of OS X is installed on your computer
Cac Reader For Mac Download
(You need to know this information for step 6)
Step 3a: Click the Apple Icon in the upper left corner of your desktop and select 'About This Mac'
Step 3b: Look below Mac OS X for: Version 10.X.X.
Step 4: Verify which exact CAC (ID Card) you have
(You need to know this information for step 6)
Look at the back of your ID card (above the black strip) for these card types. If you have any other version than the four shown below, you need to visit an ID card office and have it replaced. All CACs [other than these four] were supposed to be replaced prior to 1 October 2012.
GEMALTO TOP DL GX4 144GEMALTO DLGX4-A 144
Oberthur ID one 128 v5.5 DualG&D FIPS 201 SCE 3.2
Find out how to flip card over video
Step 5: Decide which CAC enabler you can / want to use
After installing the CAC enabler, restart the computer and go to a CAC enabled website
Optional Step 6: Update your DoD certificates:
Cac Reader For Mac Download
Step 6a. Load the DoD Intermediate certificates into your keychain
then...
Step 6b. If your CAC has a CA between 27 and 32 [and they didn't show up after 5a above] you'll need toinstall all of the CA 27 to 32 and CA Email 27 to 32 certificates manually. You can download the AllCerts.zip (http://militarycac.com/files/maccerts/AllCerts.zip) file, then double click each certificate individually to have them install into the login section of keychain. If you want to verify they are there, follow guidance on the Keychain page. Idea # 2 only.
If you receive Error: 100013, click here for instructions
Mac support provided by: Michael Danberry