Why do Windows and QTS display a login failure error even when I am not accessing shared folders via SMB?

Last modified date: 2026-09-03

Applicable Products

QTS 5.1.7 or later

QuTS hero h5.1.7 or later

Explanation

By default, Windows tries to access an SMB server using your Windows account credentials. If these differ from your NAS account credentials, the NAS rejects the connection and logs an error in QuLog Center. Windows then shows a login prompt so you can enter your NAS credentials.

You may see this error even when you are not actively opening a shared folder. This is because background processes can also attempt SMB connections, such as:

Network printers
Antivirus software
Other background services that scan or sync with network shares

Nevertheless, this is an expected Windows behavior, not a network or security issue. You do not need to do anything.

Workaround

Since this behavior can generate repeated log entries for the same failed attempt, QuLog Center now applies a short grace period to reduce this false-positive noise. Starting in QTS 5.1.7 and QuTS hero h5.1.7, login failures from the same user, source IP address, and computer name that occur within a three-second window are grouped and counted as a single entry, rather than logged separately.

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