We’ve had exactly the same issue. Yesterday I upgraded KSC 12 to KSC 13 in the hope that might fix it, but no luck. Kaspersky support have previously suggested that I uninstall KSC, reinstall it and restore from the last backup, but I’ve not yet had a chance to do that and I’m unsure whether that will make any difference. I tried the steps posted by Markus above and as soon as the service was restarted, KSC started redownloading all the updates (13GB of them)! Attempting to clean the software updates folder as per https://support.kaspersky.com/15304 then still has no effect. We have a separate WSUS server and have no need for this function in an antivirus software. Ironically, the lack of space on the C drive as a result of this is now preventing us from installing the Windows updates to the server from WSUS!
