Great question—this is absolutely a plausible scenario, and the timeline you’ve shared makes your suspicion about Windows Update self-updating even more credible. Let’s break this down:

1. Resource Contention Is a Common Culprit #

Even when Windows Update is only downloading updates (not installing them), the wuauserv service can chew through critical server resources:

• Large update packages can spike disk I/O, CPU usage, or memory consumption. For a busy database server, this kind of contention can easily slow down or block access to high-traffic tables—exactly like the one you saw stop updating at 15:01:44.
• Background tasks tied to update preparation (like compatibility checks or staging files) might also lock system files or interfere indirectly with other services, even without obvious errors.

2. Windows Update Can Self-Update Even in Download-Only Mode #

Your hunch about self-updates is spot-on. The Windows Update service itself needs occasional updates to its own components, and this can happen even if you’ve set it to only download updates, not install them.

During a self-update:

• The service might restart abruptly or cycle through start/stop states in a way that disrupts system stability.
• Rarely, the self-update process can conflict with other services (like your database or network tools) if it modifies shared system libraries or grabs exclusive access to critical resources.

3. Your Timeline Lines Up Perfectly #

Looking at your system logs:

08/05/2019 14:58:49 The Windows Update service entered the running state.

Your application outage hit at ~15:01:44—just 3 minutes later. This tight correlation is a huge red flag for a causal link. A lot of resource contention issues don’t leave clear error traces in application logs; they just starve your workload of the resources it needs to respond to users.

4. How to Confirm This Is the Root Cause #

To verify your suspicion, try these steps:

• Check your Windows Update history (go to Settings > Update & Security > Windows Update > View update history) to see if any updates to the Windows Update agent itself were installed around that time.
• Pull up performance monitor logs from the incident window—look for spikes in CPU, memory, or disk usage tied to wuauserv or the svchost.exe process hosting it.
• Temporarily disable automatic update downloads on the server and monitor for similar outages. This is a straightforward way to isolate whether Windows Update is the trigger.

Wrap-Up #

It’s easy to think "download only" mode is totally safe, but Windows Update’s background operations are more complex than just pulling files. Self-updates and resource contention are both well-documented causes of unexpected server issues, especially on systems running critical workloads like databases.

内容的提问来源于stack exchange，提问作者user1040323