My machines downloaded an update last week (I think on 8/21). Now, they all are getting an error message from Kaspersky whenever someone logs in, and they are not updating. I have seen several topics on here talking about a bad update, but I have not seen anyone list the fix. What do I need to do to fix this?

I am fairly new, and apologize if the answer is obvious.

Are you using the Admin Kit? I've setup Global tasks to run on each group that is setup. One of the global task is the signature updates which we run every 6 hours. Also make sure that if your workstations are grabbing it from a shared folder rather than the Kaspersky update servers, that the shared folder doesn't contain the issue. Easiest fix is if you have that setup is to just rename the folder create a new folder with the same original name and run the update task on the server.

this is the fix article if you are still needing it.

http://support.kaspersky.com/wks6mp3/error?qid=208279891

use the admin kit to deploy the fix out to all your machines, and then after that run a update task against your group