Problems with MacOS X 10.9.5, CanoScan 8800F, & DD WRT

I am using DDWRT on an Atheros-based router with the vhusbdmipssf server. I have successfully shared an hp photosmart 7700 to clients on both Windows 7 64bit and OS X 10.9.5. I have also successfully shared a CanoScan 8800F to the client on Windows 7. However, on OS X, when the default Canon scanning application (MP Navigator EX) begins scanning, the vh client "resets" -- i.e., the client appears to lose all connection with the server (the scanning software says that it "cannot communicate with scanner"), the client re-displays the pop-up window with "VirtualHere USB Server Trial Edition, and the connection to the server is reestablished after clicking OK in the pop-up window. If anyone has managed to get a CanoScan working with VH, then please let me know the details.

BTW, I do not see the scanner listed if I try to add it via Settings, Printers & Scanners.


If it does that its usually a bug in the Linux kernel. Update to the latest kernel if you can.


Same issue here, with slightly different hardware:
- Canon Pixma MX375 MFD on QNAP TS-210 (latest firmware 4.1.2) or RaspberryPI Raspbian (latest kernel 3.12)
--> On OS X 10.9.5, the Client loses connection when attempting to scan as described above.
With a Windows 8.1 client, scanning worked just fine.

Looks more like a specific issue of the VH Mac Client than one with the Linux kernel...

Very cool tool, hope you can fix this!

Regards, dlx


Thanks for your feedback. ok if thats the case i can have another look. If it works with windows then its almost certainly an osx issue. Could you do the following:

1. In the VirtualHere Client -> Right click USB Hubs -> Debug Mode to turn this mode on
2. Right click the device and select USE
3. Attempt to scan so the connection drops
4. Right click USB Hubs -> Debug Mode to switch that mode off.

Send me the file /tmp/virtualhere_driver.log file on your osx machine to mail [at] and ill see if it shows any issue there.


I followed the steps, debug mode seems to be actuve, but the client didn't actually write such a log file in /tmp (despite claiming that).
Couldn't find any file with that name on the entire disk.

Maybe the normal log output already helps though.
It crashes in the moment when the preview image is supposed to be transfered from the scanner to the PC, with those two lines:

22:11:29 INFO :Server ping timeout, shutting down connection 1...
22:11:29 INFO :recv msg size failed, error 9 (Bad file descriptor)

Seems like it has an issue with large messages from the scanner...

Hope that helps,


The NAS VHServer was a little more explicit:

"[virtualhere] Error processing message (type 19). It is too big (8388661 bytes) to transmit"

Yep, that message is indeed large. The scanner seems to transmit the entire raw picture as a preview - which is too much.

Would you be able to make "it" (client issue? server issue?) support such large messages?

The issue might also have todo with how OS X Image Capture requests pictures from the scanner, maybe Windows pulls them in smaller chunks (or it's MTU related or whatever)



Wow yeah that message is huge, most msgs are about 64k, anyway i changed the client and server to support messages up to 9MB. So it should work now. Download server version 2.0.5 and client version 2.6.5


Tried it with the new Version, still the same error message on the NAS side.

I also tried a direct scan through the automated document feed with a much higher resolution, crashed the same way, but with exactly the same message size. Seems I was wrong, the message size does not come from a raw image transmitted in the message - that would have been much bigger in my second test.


Can you double check you installed the latest 2.0.5 version of the server. Right click on the server in the client and select Properties and it will show the version. Im thinking you didnt install the latest version as im pretty sure its fixed for that size urb...


right, I forgot to update the server.

No errors anymore, but the scanning process does not seem to finish (waited minutes) - the client does not get the image.

Sadly I can't send you the log file, the client still does not create one in /tmp in debug mode...


OK, i think that this printer/scanner unfortunately wont be compatible via osx