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Thread: [RESOLVED] VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

  1. #1

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    Resolved [RESOLVED] VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    I just tried to start VB6 IDE on Windows10 and got this unpleasant surprise
    Name:  vb6doesntstart.png
Views: 2175
Size:  45.6 KB
    and after clicking OK VB6 just dies.

    I have no idea why it wants DAO350.DLL as I certainly don't use it or any DAO in any of my projects, but here I'm just trying to load the IDE and no project at all.

    So what have I done since I last started VB6? In reverse order:
    • I have "updated" Win10 to version 20H2
    • I have changed the "Background apps" setting for most of the installed MS Apps to "Off"
    • I uninstalled several old programs I no longer use, and some of them failed to uninstall in some way, due to some missing files or similar (not the dao350 though).
      • One possible suspect here; "HP Officejet Pro 8000 A809 Series", I no longer have this printer, wasn't even aware it was "installed" this way, so obvious uninstalled it. However, after successful uninstall that was said to be completed on reboot - it still remains in the list. I tried this 2-3 times, so if it had a reference count on DAO350.DLL it could have removed it.
    • I ran Windows Disk Cleanup tool
    • I installed Search & Destroy Professional, anti-malware program and I have run most of the tools in S&D but haven't done anything "destructive" as far as I'm aware.


    So, what have I done since the problem appeared?
    I searched here of course, but while DAO350 comes up many times through the years, I haven't been able to find anything that addresses this problem.
    I checked "Program Files(86)\Common Files\Microsoft Shared\DAO\ and there I only find DAO360.DLL
    I tested to make a copy and rename it to DAO350.DLL but with no success.
    I was able to find the dll file at www[dot]dll-files[dot]com, but again with no success
    The problem remains.

    I searched registry for 'DAO350' and found these key locations referencing it,
    Code:
    Computer\HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{9862EB47-3C75-C4E0-A26C-A23286A77DEA}\InprocServer32
    Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WOW6432Node\CLSID\{9862EB47-3C75-C4E0-A26C-A23286A77DEA}\InprocServer32
    Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Classes\CLSID\{9862EB47-3C75-C4E0-A26C-A23286A77DEA}\InprocServer32
    Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Shared Tools\dao350.dll
    Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\SharedDlls
    Ok that may be enough info to get someone started, I hope... I'm trying to "wake up" my old ACER NB, where an old copy of VB6 and my projects should be installed, to find some comparable info on DAO350.DLL but for now this is what I have. Appreciate any input.
    M$ vs. VB6 = The biggest betrayal and strategic mistake of the century!?

  2. #2
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    Re: VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    Reinstall VB6.
    Some of us have 20H2 and VB6 works fine.

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    Re: VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    It might actually be looking for dao2535.tlb, the adapter used to keep old DAO 2.5 operations working with DAO350.DLL.

    But if this is broken there is no telling what else never got installed properly.

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    Re: VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    thanks dilettante, that might be it, but before I test with copying the tbl file from my old NB, I had a closer look at reg keys for DAO350.dll, and noticed this:
    Name:  regdao1.jpg
Views: 1986
Size:  27.1 KB
    and this:
    Name:  regdao2.jpg
Views: 1961
Size:  11.0 KB
    which looks suspicious to me, possible virus? Or could someone please check in their registry if this actually is how it is supposed to be in Win10 i.e. it's "normal"?
    TIA
    Last edited by 7edm; Mar 25th, 2021 at 03:21 PM. Reason: Fixed attached inline images
    M$ vs. VB6 = The biggest betrayal and strategic mistake of the century!?

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    Re: VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    the attachments did not upload correctly
    i do my best to test code works before i post it, but sometimes am unable to do so for some reason, and usually say so if this is the case.
    Note code snippets posted are just that and do not include error handling that is required in real world applications, but avoid On Error Resume Next

    dim all variables as required as often i have done so elsewhere in my code but only posted the relevant part

    come back and mark your original post as resolved if your problem is fixed
    pete

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    Re: VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    Ok fixed images, problem still at large.
    M$ vs. VB6 = The biggest betrayal and strategic mistake of the century!?

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    Re: VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    it would have helped if you had posted the keys, bloody hard to read in the image, but i did not find any data like that in my registry
    i do my best to test code works before i post it, but sometimes am unable to do so for some reason, and usually say so if this is the case.
    Note code snippets posted are just that and do not include error handling that is required in real world applications, but avoid On Error Resume Next

    dim all variables as required as often i have done so elsewhere in my code but only posted the relevant part

    come back and mark your original post as resolved if your problem is fixed
    pete

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    Re: VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    Nor did I
    Just "normal" DAO.DBEngine.35 entries, no garbled keys or data

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    Re: VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    Sorry for not getting back earlier, but my investigation into whether I had been infected by malware or not revealed that one of my HDDs was in the process of failing and had to be replaced (took 2 days to copy 350gb of data to a spare drive), and my boot drive looked to be not far behind (a Seagate Barracuda, failing 3 of the SeaTools tests) and have now been replaced with a 2 Tb SSD. So, ironically this "issue" probably saved me from a fatal crash all together.

    Anyway, up and running again, and after copying dao350.dll and dao2535.tlb from my old notebook, and re-register the former, VB6 now seems to work again. I also had to reinstall latest SP for SmartCode 2013 for VB6 to make the add-in to show and work. So "something" have certainly messed with my PC, but a deep inspection of my system hasn't shown any sign of (known) malware, thus not quite sure what has happened.

    As the original problem posted now seems to be gone and if no one has more to add I guess I'll mark the topic resolved, even if all those suspect cryptic keys and values still remain in the registry and they are all over the place, not just for DAO350.

    To address westconn1's request, here are the keys in the images above (as that part of the images were cropped somehow);
    Code:
    Computer\HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{9862EB47-3C75-C4E0-A26C-A23286A77DEA}
    and
    Code:
    Computer\HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{9862EB47-3C75-C4E0-A26C-A23286A77DEA}\InprocServer32
    but after register da0350.dll again, several new CLSID keys for have been added for DAO.DBEngine.35, lacking all these "cryptos", so maybe the old keys just can be deleted, although I would like to know more about how and where they came from. Is there anyway to get more specific information out of a CLSID like 9862EB47-3C75-C4E0-A26C-A23286A77DEA here?

    EDIT: BTW, in case it means something to someone, the exact same keys are in
    Code:
    Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WOW6432Node\CLSID
    and
    Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Classes\CLSID\
    Last edited by 7edm; Apr 3rd, 2021 at 06:17 AM. Reason: Added info
    M$ vs. VB6 = The biggest betrayal and strategic mistake of the century!?

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    Re: VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    SSD Data Recovery Best Practices

    ... That being said, many SSD users assume their SSDs are more reliable than HDDs because their lack of moving parts should theoretically mean less opportunity on the whole for something to go wrong. Unfortunately, this is incorrect.
    Long story short: better keep to a complete backup process if you are going to hang your hat on SSD.

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    Re: [RESOLVED] VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    My PC is running Windows 10 Pro 22H2 version. I found solution for this problem.

    #I checked "Program Files(86)\Common Files\Microsoft Shared\DAO\ and manually downloaded DAO350.DLL

    But not running VB6.


    Solution-
    I downloaded and installed REVO UNINSTALLER PRO software.

    I opened file locations in Vb6.
    C:\Program Files (x86)\Microsoft Visual Studio\VB98

    1. Select VB6
    2. Right click and click 'install with Revo installer pro'.
    Successed
    100% Working
    Attachment 186393Attachment 186394

  12. #12
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    Re: VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    Quote Originally Posted by dilettante View Post
    SSD Data Recovery Best Practices

    ... That being said, many SSD users assume their SSDs are more reliable than HDDs because their lack of moving parts should theoretically mean less opportunity on the whole for something to go wrong. Unfortunately, this is incorrect.
    Cannot find that citation above under the link you've posted ... and even if I'd have been able to -
    my own experience (and also the results of several hardware-sites and -journals over the last years,
    show that modern SSDs have a far better long-term reliability, compared to magnetic disks.

    Over the last decade, I never had an SSD failing on me (mostly Samsung-SSDs ... two of them are 8 years in use by now).
    Compared with the decade before that (where I used magnetic disks), the average lifetime-until-failure was about 3 years on average.

    Quote Originally Posted by dilettante View Post
    Long story short: better keep to a complete backup process if you are going to hang your hat on SSD.
    Well, Backups should be done for more reasons than potential hardware-failures.

    Olaf
    Last edited by Schmidt; Dec 9th, 2022 at 04:20 PM. Reason: meant Samsung-SSDs, not Toshiba-SSDs

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    Re: [RESOLVED] VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    You've had extremely bad luck with spinning HDs... 3 years is much shorter than most of mine have lasted, I've got 6 hooked up now between 8 and 10 years of 24/7 uptime. In fact only 1/12 is *less than* 3yo right now.

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    Re: [RESOLVED] VB6 fail to start on Win10 20H2 - Can't find file 'DAO350.DLL'

    Quote Originally Posted by fafalone View Post
    You've had extremely bad luck with spinning HDs...
    My scenario was probably not representative - and I'm talking about the kind of HDDs we had 20-15years ago
    (both types, 3.5" and 2.5").

    My scenario at that time was Video-Recordings from HighSpeed-Cameras (for "Sports"):
    - "in the Field", the Trainers had powerful Notebooks with the largest 2.5"HDDs I could find at that time...
    - "in the Trainigcenters-Offices", these Notebook-HDDs were archiving their recordings onto Servers with large RAID-Arrays
    ..(after archiving to the Server, the Notebook-Recording-HDDs were cleared and "the cycle continued")

    So, the "throughput-rate" (delete/full overwrite) due to these cycles,
    was several times higher than "normal Office-usage" of course -
    but that's where my "3years on average" came from.

    FWIW, here's a recent study from a cloud-vendor
    (the scenario does no have my "complete-overwrite-rate" either of course, but the trends should be quite clear)...
    https://allinfo.space/2022/09/15/bac...dds-over-time/

    Olaf
    Last edited by Schmidt; Dec 9th, 2022 at 04:24 PM.

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