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My Dell Inspiron 9400 originally shipped with Windows XP, but came with a free upgrade to Vista. It also has a built-in Dell TrueMobile 355 Bluetooth + EDR module, so I decided to get a Bluetooth mouse to use with it. One slick advantage of having this built-in Bluetooth adapter is that a Bluetooth mouse can connect to it directly and there is no need to plug in an external USB Bluetooth 'dongle' for the mouse.

My mouse is a Microsoft Bluetooth Notebook Mouse 5000. Every once in a while, I had to reset the Bluetooth connection to get my mouse to re-connect, or turn the mouse off then back on, but it was never frequent enough to complain about it...

Originally, I decided to wait to upgrade to Vista until SP1 at least came out, but now that SP2 is out, a month ago I upgraded to Vista. Then I began having a problem with my mouse not connecting automatically following a reboot, and disconnecting from my laptop whenever the computer locked, and sometimes when the Vista UAC prompt appeared. It was a very frustrating problem to say the least.

I contacted Dell Support about this, but they instructed me to install the Vista drivers on their website, which I had already done (and did again). The problem still persisted. A Google search revealed Microsoft Knowledge Base Article 970408, which described the problem. There was no 'fix', but the suggested 'workaround' was to disable then enable the Bluetooth radio via a hardware or software switch. Pressing Fn + F2 twice on my laptop brought back the connection, but did not fix the cause of the problem.

Every few days, I checked the Microsoft KB article for an update to 'fixed' status. Just the other day, to my surprise, there was a fix offered for both 32 and 64 bit versions of Vista. I downloaded and installed the patch for my version (32-bit) and voila, the mouse seemed to work following a reboot, and when the UAC prompt appeared. But the first day, once my computer locked itself, the mouse stopped working! I returned to the article, but nothing new was there. I reported the problem to MS, but there is never any feedback from such submissions...

Bluetooth Power Settings

Bluetooth Power Settings - Click to enlarge

Then it occurred to me what might be happening: when the computer locks, sometimes the peripherals are 'put to sleep' to save power. I checked in Device Manager and found what seems to have taken care of this once-and-for-all - Power Management settings. Click on the image to the right to see a close-up:

You need to prevent Windows from disabling the adapter to save power. This has worked flawlessly for me. Hopefully this helps someone else out who is experiencing the same problem.

-Dan