Once in a while you can look on your server with the Kaspersky Administration kit. And you use tree size to see how much disk space you have left. Certainly you see that the FTserver folder is large with disk size.
How to solve this issue? Well the easiest and friendly way is to use the Kaspersky Administration kit to delete all old tasks.
No you have to delete them all to space up your disk. So after you have delete these tasks you should look with tree size again to see how large the folder is.