Lightroom: Missing .dll file error message on launch

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  • Updated 1 year ago
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When I try to start Lightroom it gives me a missing .dll file error message? I cannot find out how to fix this problem. I would purchase a copy of this software if I knew it would work, but I'm not going to put out $300 for software that won't even start.
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William Rose

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Posted 7 years ago

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Jeffrey Tranberry, Sr. Product Manager, Digital Imaging

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What is the exact error message? Have you tried reinstalling? It sounds like there is a missing file. What OS are you on?
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jdv, Champion

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Well, a missing DLL is almost certainly an indication that this is Windows. So, the OP should be sure to say the /exact/ release of Windows they are trying to run Lightroom on.

My guess is that the installer cannot update a system file because it is not being installed as Administrator, or the system file or directory is locked for some other reason.

If you have recently done any other install/deinstall operations, make sure you restart the system before trying any other installation.

Try to run the installer as a local Administrator.

Try to install using a test account.
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William Rose

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This application has failed to start because mfc100u.dll was not found. Re-installing the application may fix this problem. Windows Vista Home Premium Service Pack 2.
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William Rose

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I tried re-installing, re-downloading to no avail. I also downloaded the missing dll and tried to use that. It still won't open???
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Jeffrey Tranberry, Sr. Product Manager, Digital Imaging

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I think this is a permissions level issue.

Right-Click on the installer and choose "Run as Administrator" - this should allow Lightroom to install the necessary file.
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William Rose

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Nope! Didn't work. Tried running the installer as admin. to repair and then uninstalled the program and re-installed as admin. Still coming up with the missing dll file error???
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Jeffrey Tranberry, Sr. Product Manager, Digital Imaging

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Are you running Lightroom as an admin as well? What happens if you create a new admin account and install and run from it?
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Jeffrey Tranberry, Sr. Product Manager, Digital Imaging

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You may also want to boot into safe mode and see if it runs. http://support.microsoft.com/kb/315222
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William Rose

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I am running as admin as well. I tried making a new account and running it there. I do see the missing dll files in the Adobe file when I check the c: drive but it still won't load?
I haven't tried booting in safe mode yet. Will do in the next little while.
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William Rose

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Tried it in safe mode....but no luck. It wouldn't install because the Windows Installer Service is not available in safe mode.
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TinaC, Tier 3 support engineer

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Hi William,

A few more ideas:
-- Try turning off UAC (instructions are in Windows Help).
-- Try turning off Aero (instructions are in Windows Help).

-- Can you try booting into simplified mode (instructions below), and let me know if that works? The installer should work while you're in simplified mode, so that may be an option, too.

-- Try creating a new admin-level user account.

To disable startup items and non-Microsoft services:

1. Quit all applications.
2. Choose Start, type msconfig in the Search box, and press Enter.
3. Write down all deselected items under the Startup and Services tabs.
4. Click the General tab, and choose Selective Startup.
5. Click the Startup tab and select Disable All.
6. Select any startup items that are essential for testing the problem. If you are unsure whether an item is essential, leave it deselected (disabled).
7. Click the Services tab, and check Hide All Microsoft Services.
8. Select Disable All, reselect FLEXnet Licensing Service, and then reselect any services that are essential for testing the problem. If you are unsure whether an item is essential, leave it deselected (disabled).
9. Click Apply, and restart Windows for the changes to take effect.
10. Upon restart, you see a message saying that the System Configuration utility has changed the way Windows starts up. Click OK. When the System Configuration utility appears, click Cancel.
11. Right-click icons in the Notification Area and close or disable any startup items that are still active.
12. Launch or reinstall Lightroom.

This knowledgebase document might help you further, and it's a good one to have on hand: http://kb2.adobe.com/cps/822/cpsid_82...

thanks!
tina
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Michael Fuller

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What .dll file is missing? It's the key to solve this problem. One of your windows components is missing from PC. It's the most common problem. In this case you should download missing file from the http://fix4dll.com/ or similar dll collection. 
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Jim Kucharek

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I had the issue and fixed it.  I am running Mcafee and it was somehow seeing ui.dll and substrate.dll as threats and then interfering with them.  I deleted Lightroom Classic, paused Mcafee's virus scanning and then redownloaded Lightroom Classic.  Works fine now.  Previously, I had tried replacing the ui.dll file, rebooting, reinstalling and actually replacing windows.  Nothing worked until  I stopped Mcafee.  I have had Lightroom for years without this kind of problem but something got triggered with this download.  
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Sham Hussain

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worked a treat