Driver no longer loads

By louarnold
Oct 16, 2010
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  1. My PL2303 (USB/RS232) driver no longer loads.

    When I plug in the device, Vista goes to Windows Update for the driver and finds none. In Device Manager (DM), the annotation for the Port is Unknown device. When I try to manually install the driver through the DM, it fails. The code is sometimes 1 and other times 19, or 28), The error message is that some parts of the INF file are invalid.

    Until now, several drivers for Vista installed, although one actually worked.

    System Info says I'm running Vista Home Premiun X86-based PC, but the sticker on the laptop says Athlon 64 X2 dual-core (Acer Aspire 4530).

    Any fixes?
  2. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,233   +234

  3. louarnold

    louarnold TS Rookie Topic Starter

    Been there. That driver is in the Windows cache. I don't think it works, anyway.

    The problem with these drivers is that they come with an installer. You can't see the INF file, and so you can't see the software version number, VID and PID that the driver is meant for. All you can do is run the installer and when you next try insert the USB connector or when you go to Device Manager>Ports>USB...>Properties, and then you see info via the various tabs and buttons. In my case, I don't get that far. When I try and update the driver it keeps asking for the file ser2pl.sys, whose location I do not know, and if I did, I wouldn't know the version of the driver it is for.

    BTW: The VID and PID mean Vendor ID and Product ID. Hence the idea that these are fixed values for each product. From personal experience, these don't change from version to version of the driver.

    Note also that a MS utility called USBview displays the VID and PID of the subject adapter cable even when no driver is installed.
  4. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,233   +234

    Do any of the computers USB ports work at all?
  5. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    I can provide some info (tho don't know i can provide the answers)...
    > Correct :) The VID and PID don't change with the driver. They are hardware specific
    > VID and PID are programmed into firmware of plug and play devices by the device manufacturer. VID and PID are just a part of the Hardware ID strings the PnP hardware sends to Windows to identify itself to Windows so Windows can find a suitable matching driver for a device

    fyi... USB vendors buy their VID from which administers VIDs internationally
    That's 'cuz Windows doesn't need drivers to detect hardware and then receive a PnP device's Hardware IDs. Windows only needs drivers when it comes time to fully communicate with and USE the device functionality. (Hardware detection and receiving Hardware IDs is done at the USB/PCI hardware and bus protocol level)

    It would seem the drivers on your computer have become corrupt. And the installer is assuming driver files (or specific versions) which aren't found on your machine. Seems that serial to parallel driver is a pain for lots of different devices. See here. See if that might help.

    /* EDIT */
    btw.. I actually HAVE seen rare occasion when the VID / PID and/or other parts of a Hardware ID may change after what might appear to be a "driver update". BUT, in fact, this would only occur when one runs a vendor "update" that actually includes a firmware update. To my knowledge, only firmware changes will change the Hardware IDs

    /* EDIT2 */
    And just to clarify, only handles vendor assignments for USB bus devices. There are separate organizations that do that type ID administration for other Plug and Play buses (e.g. PCI). So it's no coincidence when one sees a PCI bus hardware ID of VEN_8086 and discovers that PCI bus vendor ID 8086 represents Intel!)
  6. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    OH. One more thought
    Do you mean to say, if you look in DM under USB category, you see some entries labeled as Unknown?? If you rt click the Unknown device under USB, Properties->Details does it llist VID and PID as 0000?? That usually indicates that Windows detected hardware and received an INVALID Hardware ID. Could be a different device problem?????

    As i believe Unknown under USB is different then "Other" which is where Windows receives valid Hardware IDs but can't find a suitbable driver to match
  7. louarnold

    louarnold TS Rookie Topic Starter

    Yes, they all work, but not with that device - the USB to Rs232 adapter. Getting the driver to properly load when you plug the device into the USb socket is where things fail.

    Yes, I think I corrupted them. There were several in the cache all with the same name and and so I could not tell the version numbers or dates. After several hours of trying to "uninstall" them, I deleted them manually. That's when this problem started.
  8. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    Well, if you've apparently been manually deleting driver files by hand and corrupted things, not sure what to tell you other then

    1) Try a System Restore to a date prior to the problem
    2) If that fails you're probably best to do a reinstall (unless you do disk image backups, then use them)
  9. louarnold

    louarnold TS Rookie Topic Starter

    When I plug the adapter into the USB socket, it appears under "Other devices" as "Unknown device". I should appear as a comm port.

    When I rt-ck Unknown device, and select Properties, all the info is for a com port. The driver it has loaded is from C:\Windows\system32\DRIVERS\ser2pl.sys. However, the error message in the General Tab says "This device is not configured correctly (Code 1). A service installation section in the INF file is invalid."
    Trying General tab>Reinstall Driver button, produces the same result, even when I pick from the list of compatible drivers.

    Q: How do I get rid of the drivers in the driver cache - the ones for this device?

    Yes, but since then I have installed several versions of the driver for the adapter, all with the same result; what I deleted is largely back.
  10. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,233   +234

    Maybe then a fresh Windows install is the best thing to do at this point. In the future, be a bit more careful when deleting drivers or other system files
  11. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    1) Ahh.. so in your case, Unknown is listed under Other category, so yes, as the errors indicate Windows can't find the driver. (Unknown implies something else when it appears under USB category)

    2) Trying to clean things up by hand at this point could be a long and painful process (with no guarantee of success). I agree with Tmagic, i think you're best approach at this point is a clean reinstall PLUS given the problems that seem to occur with this type of driver (given your history and seeing others post problems online) i;'d also suggest you do disk image backups so you can easily recover next time if driver files get corrupt for any reason
  12. louarnold

    louarnold TS Rookie Topic Starter

    OK, thank for your help. I guess its time to find the last disk image.

    It would be useful to have a way of properly removing driver in the Windows cache. Even now I see a long list of drivers for this device, most don't work and I can't tell which version is which.
  13. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,233   +234

    That long list of driver files may include drivers for other computer/motherboard configurations. If you're running out of disk space, buy a bigger hard drive. It's the number of active services that slows a Windows computer down. Be sure to format the hard drive before installing the last good image
  14. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    Hmmm... I don't think you typically need worry about removing things from driver cache (C:\WINDOWS\Driver Cache\i386). I know i never do when cleaning up driver files. Look for driver files where they normally reside on your disk. Some of the helpful tools i've found over the years

    > DriverView
    > Serviwin (Click View->Drivers)
    > DevManView

    To see the list of driver files associated with a device use DevManager -> Driver Details

    And, of course, be careful and know what you're doing before removing stuff.. And, at minimum, advise a disk image backup before removing stuff is also a good idea before you start removing :)
  15. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    OH. Just noticed Tmagic and i posted same time.. So, I'll add.....

    I'm assuming you're asking about removing driver files to fix specific driver install issues...

    As to trying to delete drive cache itself to conserve space, i think that's another topic.. I've seen much written about clearing driver cache but don't know i've read anything i would rely on. I've never tried deleting driver cache itself
  16. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,233   +234

    I have never tried to delete driver files either
  17. louarnold

    louarnold TS Rookie Topic Starter

    Thank both for your replies.
    The operative phrase was "for this device". I had not planned to remove other drivers. And this is not a space issue; I would just like to get rid of what doesn't work.

    Its now clear that the problems with this device cannot be solved, and so I wanted to remove the several versions of the drivers for it. These drivers are not actually installed, but just stored for when the device is plugged in again. Many tools see drivers only when they are installed.

    As for the location of these drivers, they're stored in Vista's system folders. Examples are:
    ser2pl.sys in C:Windows\System32\drivers
    ser2pl.sys in C:\Windows\System32\DriverStore\FileRepository\ser2pl.inf_78a854ae\
    I have 5 listed in total when I do a file search of C:\Windows\ for "ser2pl.sys".
  18. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    Yes. But that's often related to whether the device is "present" or not. (don't know if you're aware or not ) By default, Device Manager only displays devices that are currently "present" - meaning they're currently plugged in, turned on and the hardware is detected.

    Are you aware of "ghost" (non-present) devices and looking for them in DevMgr? Check if your problematic device has ghost entries in DevMgr as well and uninstall them.
    > If you plug in a PnP device, Windows detects it, installs its driver and you see it DevMgr
    > Unplug the device. You no longer see it in DevMgr but the device driver is still installed!!!
    > Drivers get removed when you UNINSTALL a device. Not UNPLUGGING a device
    > So.. just 'cuz one doesn't see a device entry in devmgr doesn't mean the device driver is uninstalled

    To enable viewing ghost/non-present devices, see here. It;s about XP but same is true for Vista and Win 7
  19. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    Interesting stuff :)

    Here's some more (and different/additional info) I found about Driver Store which is why i decided to provide it in a separate double post

    Re: DriverStore on Vista and Windows 7
    I did a bit of digging to learn more myself. Here's a quick summary of some of what i found on top of some things i already knew. Don't know if it might also help for your case

    "Driver Cache" vs "Driver Store"
    I think the term "Driver Cache" is more apt when talking about Windows 2000 and XP, While the concept of driver caching is similar for all versions of Windows
    > Driver Cache is a specific term for W2K and XP
    > Driver Store is a specific term for Vista and Windows 7
    > I think searching on the right term helps find more suitable info on the topic for for the right OS and may help avoid confusion between the two
    > IMO I also think Driver Store is a more apt description (maybe that's why MS changed it? dunno)

    See Remove a Driver Package from the Driver Store. Interesting reading, i think :)
    > While the Windows Technet article talks about Windows 7, i just tried the pnputil tool on Vista and it also works so i think should be same for Vista
    > Tool pnputil.exe doesn't exist on XP

    /* EDIT */
    A bit more info i'll add for the reader...
    > Every driver has an INF file associated with it
    > The INF file is the Driver Setup Information File. It tells Windows how to install and uninstall the driver
    > INF files named Oemxxx.inf (where xxx are digits) are INF files for 3rd party drivers (i.e. drivers that aren't included with the Windows OS distribution)
    ===> Windows usually uses the Oemxxx.inf naming convention when it installs a 3rd party driver. That's the name Windows uses to save 3rd party INF files that aren't included / stored on the Windows OS distribution media (i.e. it's a driver that didn't come included on your Windows installation disc)
  20. louarnold

    louarnold TS Rookie Topic Starter

    Thanks for all this info. Most of that I found out previously and it wasn't of much help.

    Looking for nonpresent devices didn't produce anything. I had uninstalled all the drivers for the device. This makes sense.

    The MS Technet article "Remove a Driver Package from the Driver Store"
    ( was certainly interesting. Via pnputil.exe, I managed to remove all but one oemxx.inf entry. One came up with the error "The system could not find the specified file". When I checked C:\Windows\Drivers, there was no oem22.inf or .pnf file. I used pnputil again to list the files, but that reference was no longer there. Maybe I copied the name down wrong; I'm not sure.

    Interestingly there is still a ser2pl.sys file there along with some .cat files in a temp folder under driver store. (C:\Windows\System32\DriverStore\Temp\(some GUID)\Package\ They were marked as "Security Catalog". Doing a disk cleanup did not get rid of them. I would still like to get rid of these.

    There is still another version of the same driver: serwpl.inf and .pnf. These are in the DriverStore\FileRepository, but there is no entry of any class used in the INF file. I recall that this version did not install at all and so I assume that these files are not known to the system.

    I assume that I can now safely delete these left over files?
  21. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    If the driver package/INF file isn't listed by pnputil, i would also GUESS it's OK to remove those extra files from the Driver Store BUT the key word here is GUESS. This is my best guess. I certainly don't say it with certainty that it's OK and no problems might occur if you remove them

    So if you decide to remove the files, do so at your own choice and own risk (and of course be prepared for the worst, just in case)

    btw... I don't know what type of drive image backup software you might use but speaking as one who often likes to "tweak" my own computers (and learn from doing so) I'd suggest you use imaging software that can create "incremental" backups of the drive image (I use Acronis True Image)

    • Of course, you want to create a drive image as backup before doing any Windows/driver/etc. tweaks you're not 100% sure of
    • I find that using image backup software that can create incremental backup images saves both time and disk space because they can incremental backups (not just full drive images each time)

    In any case, g'luck! Let us know how it turns out :)
  22. louarnold

    louarnold TS Rookie Topic Starter

    Hahaha, Its OK, I won't reach out and try and grab ya if deletions don't work.

    The key here is that the computer now works fine in all aspects other than these drivers. If I delete them manually, then only registry entries may be left over and these can be cleaned out by a registry cleaner. If the computer continues to work after the cleanup then I am rather safe. If rebooting works then I am 90% home.

    As for imaging, the drive is partitioned to contain the OS in one part and data in all the other parts. It all goes on 1 or 2 DVDs and I 'm not sure incremental backups make much sense for OS parts. I'll get back to you if it all falls apart. Otherwise, thanks very much for the URL to that MS Technet article; that saved the day. It also points out just how complex the driver system is in Windows. I still have not found a tool for XP similar to pnputil.
  23. louarnold

    louarnold TS Rookie Topic Starter

    Bad news. The laptop is dead.
    I tried imaging a partition on the hard drive. I thought I succeeded but it failed on the recovery and in the process destroyed the boot partition. I then tried the factory state recovery DVDs that I had made when I first bought the laptop. They failed part way through.
    Now I am stumped.
  24. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    Hmmmm. I wonder if the drive itself might have failed?? Otherwise, I'm stumped as well

    I don't know of any driver cache tools for XP either.

    But i can mention another useful MS tool for Windows Device Management and reporting/configuring Device Manager data. Don't know if you've ever used / played with devcon tool?
    • I'd only recommend it for the intermediate to advanced user familiar with Windows device data (sounds like you are :) )
    • It's a command line level interface to Device Manager from MS. (But devcon provide LOTS more detail and driver info then DevMgr does)
    • The link i provided above is about XP but devcon also work on Vista and Windows 7 (be sure to run it from a command prompt with Admin rights)
    • Do a bit of googling and you'll find far more documentation and examples about using devcon commands, what they can do and how to use them
    And g;luck with your problematic computer! ;)
  25. louarnold

    louarnold TS Rookie Topic Starter

    Nope. Have never used devcon. I wil try after I get the laptop.

    What failed was the Clonezilla software. Its been reliable for for the desktops, but not the laptop it seems.

    Also, the Recovery DVDs I made were perhaps from a previous laptop, that I traded back for a better model. (The CDs are marked as Vista Basic and I was using Home Premium.) I was rushed at the time and did not make Recovery CDs for the current one. The other possibility is that I made the CDs and then repartitioned the drive. And then did not image that again.

    In any case, its dead. GParted Live doesn't work on it either, so I can't try to go back to the original partitions sizes - of which I have a record.

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