Microsoft released its latest cumulative update for Windows 10 PCs and phones today, bringing a wide range of fixes and improvements, and bumping the build number up to 10586.318.
For PCs, though, the update - which is documented on Microsoft's site as KB3156421 - may also introduce a fresh issue for some devices. Luckily, there's a possible fix if your PC is affected.
Microsoft's John Wink, Senior Program Manager Lead working on Windows 10 updates, said on Reddit today that "if you find that your PC is abnormally slow after installing the update, you may be seeing a problem that I've been trying to track down for a couple of weeks."
Here’s something you can try to see if it alleviates the symptom. I’d love to hear the results of this test, and could really use your help in gathering additional information if indeed it rectifies the symptom for you. Please give this a shot and post your results to this thread. Thanks!
Steps to disable Cortana: Click in the Cortana search box to bring up Cortana
Click the Notebook
Move the slider under “Cortana can give you suggestions, ideas, reminders, alerts and more.” to “Off”.
In reply to another comment in the thread, he also noted:
It's actually not a very wide-spread issue, it's just that when you hit it, it's incredibly annoying. If disabling Cortana resolves the symptom, that means we know what's happening and we'll probably roll a fix into a future update. But I need some examples of cases where this workaround works to justify rolling that fix in. :-)
If you encounter the issue, and the suggested workaround resolves the issue, be sure to let us know in the comments below - and don't forget to share your findings with John over on Reddit too.