Arduino IDE 1.6.6 SLOW to start up, but can't disable Win 10 bluetooth

I have Windows 10 running on a MS Surface Pro 3. I have the Arduino 1.6.6 IDE. When I go to program sketches on the road, without a USB cable and an Arduino board actually attached, the Arduino IDE is very S-L-O-W to load (~20 s), and also slow to save, compile, etc. In fact, it seems to freeze up my machine for periods of 20+ secs at a time!! I have read several previous threads about slow starts. One of these threads suggested replacing the "rxtxSerial.dll" file with a patched version, but this fix was apparently for an earlier version of the IDE -- that same DLL file does not seem to exist in my current version (or it has been moved to some other directory). Another earlier thread suggested turning off all Bluetooth input altogether, but that is NOT A VIABLE OPTION for me, because my MS Wedge Touch Mouse runs off Bluetooth, and so does the handheld pen that's used to control the Surface!

Is there some way to stop all the errant COM port scanning by the IDE, or to allow my Bluetooth to peacefully co-exist, somehow, with the Arduino IDE, without causing it to freeze up? Help, someone!?!?

I have been suffering from 1.6.6. on Wind10 too. After weeks of trying out different stuff mentioned on the forums and elsewhere on the interwebs.

I just downgraded to 1.6.5 which works pretty well.

With my MS Surface Pro 3 running Win 10, the Arduino IDE (v1.6.6) is almost unusable. It "hangs" for up to 1 min just starting up. It also hangs for a minute or so whenever you try to open a sketch, close a sketch, save a sketch, compile a sketch, or run any Tools!! This is intolerable.

Following up on suggestions from other threads, I tried turning off Bluetooth (from the Win 10 Action Center, right swipe on screen). Unfortunately, this had essentially no effect, and it did not solve the problem for me. However, placing the Surface Pro 3 in full Airplane Mode (with BOTH WiFI and Bluetooth OFF) made the hang-ups go away! This is the only workaround I have discovered.

The Airplane Mode workaround allows me to use the Arduino IDE 1.6.6 to write and run sketches from my Surface Pro 3, but I pay a huge price. I cannot use my mouse (a MS Wedge Touch mouse, which uses Bluetooth), and I cannot use the Surface in tablet mode, which requires the use of the MS Stylus Pen -- which ALSO uses Bluetooth. Nor can I stay online, unless I hook up to a hardwired ethernet, because I have to turn off the WiFi, too.

ARDUINO Experts: Please, please fix this very serious bug!!!

Has anyone else discovered any better workarounds?

As suggested in the first reply by Calcen, have you tried to go back to 1.6.5 ?

Same issue for me, 1.6.5-r5 works well on my windows 10 64bits. Versions 1.6.7 and 1.6.8 behave like 1.6.6

I thought it was time to bump this thread. All Arduino IDE's from version 1.6.7 up to the current one, 1.6.12, give the identical symptoms on a Microsoft Surface Pro running Win10: the interface seems to 'hang' when first starting up, and it also hangs on ANY FILE SAVE, for periods of up to 1 minute, before behaving properly.

I have discovered that turning off the Wifi radio eliminates this problem completely (either turn off the WiFi alone, or using Airplane mode, which also disables Bluetooth. The problem is WiFi). The "hang" problem re-appears immediately the moment WiFi gets re-enabled. This seems to be some kind of a problem associated with the way Java/IDE discovers the COM ports in Windows, I'm guessing.

Does anyone know of a fix or workaround?!? I need to be able to have WiFi connectivity as I develop sketches.

Did you ever resolve this? I’ve got the same issue out of nowhere on an ASUS laptop running win 10 pro 64bit…