...or at the end of a unit, I should say.
Sometimes, at the end of an x17 work unit, when it's being uploaded to the server, the upload progress in the log will get all the way to something like 97%, and then it will stop producing messages. There are no messages saying that the WU was invalid or anything. Internet will stop working at this time too.
A new work unit, having been received when the prior x17 reached 99% "complete" (not 99% uploaded), will continue to just sit and wait, even though the GPU has no work to perform. The CPU slot will continue to run, of course.
The only way I've been able to fix this situation is to power down the DSL modem, then power it up and reboot the PC. Just recycling the DSL modem will not provide the kickstart that the folding client needs to retry the failed WU upload.
Upon PC reboot and restart of the folding client, the partially-uploaded x17 WU will retry the upload, sometimes several times. Eventually, I get back an "ALREADY GOT" message, followed by "DUMPING WORK", and the new x17 WU begins processing in the GPU slot. Checking my points records, I see that I am indeed getting credit for these buggered up WUs, and the credit is being granted at the time of the network hang, not after my reboot (it's easy to tell when the freeze happened 8 hours ago, that I got the credit back then).
This is a real pain in the ass, because fixing it requires me to be present, conscious, AND at my computer! If it happens when I'm not home, asleep, or doing something else around the house, I could lose anywhere from 3 to 16 hours of processing time. This hurts not only my production, but the folding projects that my PC is taking part in.
The DSL modem is a simple Netgear model, only about a year old. Have had no problems with it, and even now when this happens, it always coincides with the tail-end of an x17 UPLOAD, never at any other time. It seems to happen about every third or fourth x17 upload, not every time.