Troubleshooting Reference for Skype for Business File Transfer Issues

In my last post, I mentioned a co-worker alerted me to problems with file transfers in Skype for Business failing.

I did promise to do a post on her situation once we resolved the issue. Well, we resolved it!

I documented the troubleshooting steps we took. Many didn’t help our problem, but they might help yours. Like most technical issues, what fixes one instance may not fix another.

The Problem: Skype for Business Locks Up When Files Sent to the User

From the co-worker’s original email:

“Almost every time someone sends me a document through Skype [for Business], it locks up. I have to shut it down through Task Manager. It’s happened since Lync, and was never fixed. Not sure what it is, but maybe you could find something on it?”

A very specific circumstance. What happens if she sends files through Skype4B? According to her, it would work sometimes, but not always.

File Transfer Troubleshooting Steps

First, make sure file transfers are enabled for the user! I covered this in the last post, under the “When to Turn File Transfer Off” section. All the troubleshooting in the world won’t help if your user has file transfers disabled.

Now, assuming file transfer is enabled (it was for the co-worker), let’s proceed with troubleshooting.

Step 1: Check the Logs for Errors

On a Windows system, you’ll find system logs in the Settings (Windows 10)/Control Panel (Windows 7/8).

The Skype for Business client also records logs, if you have it set up to do so. Here’s how to check that.

  1. In the Skype for Business client, click Tools –> Options.
  2. The Options window will open, showing the General Options. In the third box, titled, “Help your support team help you,” you’ll see two logging options. One is a dropdown menu titled, “Logging in Skype for Business” with three choices: Off, Light, and Full.
    • This was pre-set upon install, but you can change it with a click. We set all customers to Full by default.
  3. Where do you find these logs? In the Tracing folder. You’ll find this at “C:\Users\YOURUSERNAME\AppData\Local\Microsoft\Office\[16.0 or 15.0]\[Skype for Business or Lync]\Tracing.
  4. The other logging option is a checkbox for, “Also collect troubleshooting info using Windows Event Logging.” This tells Skype for Business to feed logging data to Windows’ event logs.
Turn on Logging in Skype for Business

We pored through these logs. I found several instances of Skype4B starting properly, closing properly, one or two “Error: Improper Shutdown” messages…but no explicit file transfer issue. The shutdown errors could have been the file transfer freezing Skype—but they could also have come from my co-worker force-quitting after the freeze.

Once we knew her logs were running, we tried a test. I sent her two files via Skype4B Conversation – a simple image, and a big Word document. Of course, Murphy’s Law being what it is, they worked perfectly!

While we waited for another instance of the error, we tried the next step.

Step 2: Run Diagnostics

Next, we ran DirectX Diagnostics (dxdiag.exe).

Now, I know what you’re thinking. This has nothing to do with Skype for Business. Why even try? Normally I wouldn’t have…but my co-worker said something that prompted us to. She said she recalled the screen flickering when the freeze occurred. Not always, but often enough that she remembered.

That could indicate a video issue. Quick, easy (and built-in) way to check for those is DirectX Diagnostics.

Running DirectX Diagnostics is simple on any Windows PC. Click Start, and enter “dxdiag” (no quotes) into the search box. Click the “dxdiag.exe” result.

The DirectX Diagnostics tool opens up, and runs a scan on your video and sound components. If all’s well, you’ll see results like this:

DXDiag Screen

Which we did. On to the next idea.

Step 3: Third-Party Block

If file transfer is enabled, and the client appears not to have any serious problems…was something ELSE blocking Skype for Business file transfers?

I turned to Almighty Google to check. Soon enough I found a possibility—Malwarebytes. If Malwarebytes Home or Premium is running, it could see Skype for Business file transfers as a malware vector, and block them.

The solution? Updating the Skype for Business client. More on that in a moment.

There’s also a workaround: adding Skype for Business as a “Web Exclusion” within Malwarebytes*.

  • Open Malwarebytes.
  • Click the Web Exclusions tab.
  • Click the “Add Process” button.
  • Enter the Skype for Business .EXE file path.
  • Save, and restart the computer.
Malwarebytes Web Exclusion

Skype for Business 2016 freezes on a computer that has Malwarebytes is installed – Microsoft Support

*IMPORTANT: This does NOT work on all versions of Malwarebytes. Check your version.

We use a corporate site license for our Malwarebytes, so users don’t have admin control on their local machines. Including my co-worker’s. Next!

Step 4: Video-Based Screen Sharing Getting in the Way?

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