Access official resources from Carbon Black experts
The current design is such that the sensor always attempts to download from cloud even if Cb Mirror has been unchecked from policy.
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Cb Defense: How To Configure Local AV Scan
Cb Defense: How To Set Up A Local Mirror for AV Signature Updates
Cb Defense: How to tell where Local AV Signature update was downloaded from?
Cb Defense: Verify the Latest Local Scanner Signature Version