Ok, this is getting frustrating. Here's the whole backstory: I have a Macbook Pro 13", (early 2011) that is running Parallels with Windows 7 without any real issue. I used this unit for three years heavily in both Windows and Mac environments and had little to no problems with it, other than some annoying behavior of Parallels. On the recommendation of some colleagues, I decided to give Fusion a try when it came time to replace the MacBook with a new model, which is where I'm at now. I just purchased another Macbook Pro Retina 13" (mid 2014) and did a full migration from the old unit to the new one. With this migration, Parallels transferred over flawlessly and still works well even though they say the version I have isn't compatible with Yosemite. The only issue is some pretty annoying resolution issues. Anyway, I decided to try Fusion and see if this fixed those issues (and others that I was experiencing).
I installed the trial version of Fusion 7.1 a few weeks ago and was initially very impressed, with one major exception: I couldn't get my Prolific Usb to serial adapter to connect to the Windows VM. When I plug in the USB I hear the 'DaDunk' Windows tone for a device connect and then a few seconds later it disconnects (another "DaDunk'), after which point it just keeps repeating the same tone over and over. I searched all over the forum and found a link to an article in the KB that gave some troubleshooting steps - none of which worked, and finally ended with instruction on adding a line to the .vmx file that started a USB analyzer. I tried this, but kept getting an error saying that the term "true" wasn't valid so instead it used "false". Since this didn't work, I removed the line from the .vmx file at which point I got a "VMX file corrupted" message and could no longer start my Windows VM.
Today, I purchased the full version of Fusion 7.1 and, after fully uninstalling all traces of the previous attempt, installed it all over again, using the Windows image that was already present in Parallels. It should be noted that the serial adapter works fine in the Parallels VM. After installing everything, I encountered the same issue fro the previous attempt and had the same results. I re-installed the drivers, and suddenly it worked.....once. after a few minutes the connection to the USB was again lost. It's as if the USB can't stay connected to the VM. I made sure that Parallels was totally shut down to ensure there were no conflicts.
Thoughts?