High CPU usage in Arduino IDE 1.8.7 (Win10)

I get high (40-50%) CPU use when I run the Arduino IDE on Windows 10, as a portable installation. It's noticeable as it causes the fans on my laptop to spin up and stay on continuously, which is unusual.

I can start the IDE without the problem occurring, and CPU usage doesn't go up until I switch to a different window and back again. You can see the contrast in the screenshot here.

On the process list, almost all usage is down to 'Java(TM) Platform SE binary (32 bit)'.

I tried turning off antivirus protection as other threads have suggested, but no luck.

Different antivirus have different OFF levels with some keeping watch in the background despite being told to be OFF.

Ensure yours truly is OFF by checking what else is still running after maybe using Task Manager to check both services and applications.

Also which particular version of the IDE ?
Other software can also on occasion hog down JAVA so to check further kill any other apps etc. that are not vital to the system.

If it is the desktop IDE you could also try turning off "Check for updates" in the preferences.
See if that also helps.

Some older hardware capable (just) of win 10 can also be a PITA especially laptops.
Many of the older win 10 lappy's came with only the minimum spec to run win 10 home versions.

Thank you for the reply, apologies for the slow response.

I've since gained some more understanding of the problem - clicking away from the Arduino window and back again seems to cause it to enter its state of high CPU use. From here, scrolling, typing, or compiling code makes no difference and CPU use stays high. But clicking on a menu or changing tab makes the CPU use drop back down to normal levels.

The antivirus doesn't seem to be the problem since a) the antivirus process is not what's taking CPU time, and b) CPU use rises and falls based on actions within the Arduino IDE.

Turning off "Check for updates" doesn't help.

Should I report this as a bug?

If you wish to report it that is up to you.
Would be counterproductive for me to do it as I don't really suffer the issue so much so cannot provide enough information to help them debug it.

Another thread on what appears to be the same situation.

Ah yes I see it's getting plentiful discussion over there. I'll wait and hope the developers are already on the case.

Hi paulrd,

I think I found a solution.


  1. Replace the java folder in Arduino IDE 1.8.7
  2. Use Arduino IDE beta 1.9 or currently hourly build

For more details see:



Thanks, yes, I saw that in the other thread. Tried option 1, it worked!

I found that arduino 1.8.8 is much better for w10. V 1.8.7 had issues, I fully agree.