SyncServer.exe and distnoted.exe run CPU at 50%

I have the same issue. There are a number of posts on this issue -- however none of the posts and suggested fixes have worked for me. Out of curiosity, what antivirus software are you using? For me this problem started when I installed Kaspersky 2015. Kaspersky support blames Apple, Apple blames Kaspersky. Neither company seems to respond to any of the forum posts / questions.

I'm running Windows 8.1 as well.

I have this same problem, too. I just updated to Windows 10 and updated my Kaspersky AV to accommodate. When I looked at my resource monitor, I saw that these two files distnoted.exe & siyncserver.exe were taking about 48% of my CPU, each! I killed the tasks and my CPU usage went back down to 8%.

I'm not sure if this is related, but iTunes 12.2 and 12.2.1 both seem to have a CPU usage issue when a Get Info editor is opened (just opened, this happens without executing any edit or update operations) - Task Manager shows iTunes' usage jumping to > 50%. Not related to specific AV (I see this on systems using AVG, Windows Defender, and Vipre) or to a specific edition of Windows (same symptoms on Win 7, 8.1 and 10). There have been reports of a similar issue on the iTunes for Mac forum, suggesting that this may be a problem with the core iTunes application.

However, I don't see any specific problems with either syncserver or distnoted processes, which would at least support the suggestion that this could be a conflict between iTunes and Kapersky. Obviously both cases could be different consequences of a common problem.

Same issue here. My only resolution so far is to manually kill the services when I am not using Itunes. I noticed lag in games about a week ago so I'm not sure how long I've had the issue but it seems to be new for me. I'm running Kaspersky Internet security 2015 and pause the protection has no affect on CPU usage when the apple process are running away