Managing Installed Drivers

Inside Out: Create a safety net before tinkering with drivers

When you install a new, unsigned hardware driver, Windows automatically attempts to create a new System Restore checkpoint. That doesn't mean it will be successful, especially if a problem with your System Restore settings has caused this utility to suspend operations temporarily. To make certain that you can roll back your changes if necessary, set a new System Restore checkpoint manually before making any kind of hardware configuration change. 

Inside Out: Make sure that update is really an update

How do you know whether a downloaded version is newer than the currently installed driver on your system? A good Readme file should provide this information and is the preferred option for determining version information. In the absence of documentation, file dates offer some clues, but they are not always reliable. A better indicator is to inspect the properties of the driver files themselves. After unzipping the downloaded driver files to a folder on a local or network drive, right-click any file with a .dll or .sys extension and choose Properties. On the Version tab, you should be able to find details about the specific driver version, which you can compare to the driver details shown in Device Manager.

TROUBLESHOOTING

Your computer experiences sporadic blue screens, lockups, or other strange behavior

When your computer acts unpredictably, chances are good that a buggy device driver is at fault.

If you're experiencing unexplained computer problems, using a powerful troubleshooting tool called Driver Verifier Manager (Verifierexe) is a terrific way to identify flawed device drivers. Instead of your computer locking up at a most inopportune time with a misleading Blue Screen of Death (BSOD), Driver Verifier stops your computer predictably at startup with a BSOD that accurately explains the true problem. Although this doesn't sound like a huge improvement (your system still won't work, after all), Driver Verifier Manager performs a critical troubleshooting step: identifying the problem. You can then correct the problem by removing or replacing the offending driver. (If you're satisfied that the driver really is okay despite Driver Verifier Manager's warning, you can turn off Driver Verifier for all drivers or for a specific driver. Any driver that Driver Verifier chokes on should be regarded with suspicion, but some legitimate drivers bend the rules without causing problems.)

Driver Verifier works at startup to thoroughly exercise each driver. It performs many of the same tests that are run by WHQL as part of the certification and signing process, such as checking for the way the driver accesses memory.

Beware: If Driver Verifier Manager finds a nonconforming driver—even one that doesn't seem to be causing any problems—it will prevent your system from starting. Use Driver Verifier only if you're having problems. In other words, if it ain't broke…

To begin working with Driver Verifier Manager, type verifier at a command prompt. In the Driver Verifier Manager dialog box, shown next, select Create Standard Settings. In the next dialog box, select the type of drivers you want to verify. Unsigned drivers are a likely cause of problems, as are those created for an older version of Windows.

When you click Next, you get a list of all currently installed drivers that match the conditions you specified. Note that the list might contain a mix of hardware drivers and some file-system filter drivers, such as those used by antivirus programs, CD-burning software, and other low-level system utilities.

At this point, you have two choices:

• Go through the list and make a note of all drivers identified and then click Cancel. No changes are made to your system configuration; all you've done is gather a list of suspicious drivers, which you can then try to remove or disable manually.

• Click Finish to complete the wizard and restart your computer. Don't choose this option unless you're prepared to deal with the consequences, as explained in the remainder of this sidebar.

If your computer stops with a blue screen when you next log on, you've identified a problem driver. The error message includes the name of the offending driver and an error code. For information about the error codes, see Microsoft Knowledge Base article 229903, "Partial List of Possible Error Codes with Driver Verifier," at w7io.com/2401. (Although this article is specifically for Windows 2000, the information is valid for Windows XP, Windows Vista, and Windows 7.) To resolve the problem, boot into Safe Mode (press F8 during startup) and disable or uninstall the problem driver. You'll then want to check with the device vendor to get a working driver that you can install.

To disable Driver Verifier so that it no longer performs verification checks at startup, run Driver Verifier Manager again and select Delete Existing Settings in the initial dialog box. Alternatively, at a command prompt, type verifier /reset. (If you haven't yet solved the driver problem, of course, you'll be stopped at a BSOD, unable to disable Driver Verifier. In that case, boot into Safe Mode and then disable Driver Verifier.)

You can configure Driver Verifier so that it checks only certain drivers. To do that, open Driver Verifier Manager, select Create Standard Settings, click Next, and select the last option, Select Driver Names From A List. This option lets you exempt a particular driver from Driver Verifier's scrutiny—such as one that Driver Verifier flags but you are certain is not the cause of your problem.

Note:

You can read more about Driver Verifier online in Knowledge Base article 244617, "Using Driver Verifier to identify issues with Windows drivers for advanced users"(w7io.com/2402).

Inside Out: Manage Plug and Play drivers

Removing and reinstalling the driver for a Plug and Play device requires a little extra effort. Because these drivers are loaded and unloaded dynamically, you can remove the driver only if the device in question is plugged in. Use the Uninstall button to remove the driver before unplugging the device. To reinstall the device driver without unplugging, open Device Manager and choose Action, Scan For Hardware Changes.