![Longtime Bug: Firefox High CPU usage ucrtbase.dll!beginthreadx+0x100 · Issue #32 · sandboxie-plus/Sandboxie · GitHub Longtime Bug: Firefox High CPU usage ucrtbase.dll!beginthreadx+0x100 · Issue #32 · sandboxie-plus/Sandboxie · GitHub](https://user-images.githubusercontent.com/38260267/82126970-2bc45680-9765-11ea-9c9a-bf9eaf414c21.png)
Longtime Bug: Firefox High CPU usage ucrtbase.dll!beginthreadx+0x100 · Issue #32 · sandboxie-plus/Sandboxie · GitHub
![Why does Firefox consume a lot of CPU even when closed? I thought an update was in progress, so I let it run for an hour, but it still used 50% CPU. Why does Firefox consume a lot of CPU even when closed? I thought an update was in progress, so I let it run for an hour, but it still used 50% CPU.](https://preview.redd.it/why-does-firefox-consume-a-lot-of-cpu-even-when-closed-i-v0-ouf98z84jlfa1.png?auto=webp&s=b47fdcb20838295963e961c5f7d6e9f4065a5f7c)
Why does Firefox consume a lot of CPU even when closed? I thought an update was in progress, so I let it run for an hour, but it still used 50% CPU.
![firefox - Debugging high (near total) CPU/memory usage of "Web Content" application on Linux Mint - Unix & Linux Stack Exchange firefox - Debugging high (near total) CPU/memory usage of "Web Content" application on Linux Mint - Unix & Linux Stack Exchange](https://i.stack.imgur.com/D8KzA.png)
firefox - Debugging high (near total) CPU/memory usage of "Web Content" application on Linux Mint - Unix & Linux Stack Exchange
![Microsoft fixes 5 year old Windows Defender bug that affected Firefox's performance - gHacks Tech News Microsoft fixes 5 year old Windows Defender bug that affected Firefox's performance - gHacks Tech News](https://www.ghacks.net/wp-content/uploads/2023/04/Windows-Defender-Firefox-CPU-usage-before-vs-after-bug-fix.jpg)