After Windows 7 update bluetooth doesn't work anymore.

he problem appeared in two different laptops (Lenovo and Fujitsu). The bluetooth hardware is not visible in device manager anymore, but unrecognized device appeared. Driver reinstall doesn't help. Driver installation setup says there is no bluetooth hardware.
PC Suite is installed , worked fine before.

How to restore bluetooth?

Windows updates are not perfect at matching hardware and sometimes they give you the wrong driver. You could try going to control panel\device manager; find your bluetooth device and open the properties window. Under the Driver tab tell it to roll-back driver.

Then manually go to windows update and if the bluetooth driver is there then right-click and select "hide permanently".

The 'roll back' option is not available there (disabled). Is ther a way to restore it manually? I guess some generic Win driver has gone wrong. Present drivewr for the "unknown device" is 'usbfulter.sys'.

If there is no rollback then there wasn't an "old" driver for that device. As for the unknown device - try uninstalling it, remove the bluetooth usb, reboot.

Do you have an actual driver disk that came with your device or did it always use W7 generic? If you have drivers then put in the disk when you hit the desktop sign-in after reboot has posted.

This is a laptop built in bluetooth. At some moment my bluetooth device disappeared and cannot be detected in the system, but unknown usb device appeared.

Just try uninstall and then reboot. When it comes up with new hardware, allow it to search the internet.

Tried, it automatically starts as the same unknown usb device.

Can you try to roll back to any previous system restore point?

If you already uninstalled the bluetooth in order to force the system to reinstall the drivers, generic or not, I would say that you have now one of two options:

- Uninstall from device manager the full usb devices;
or
- Go into registry and delete every reference to bluetooth:

or maybe even both

I am sure all of us had problems like this in the past, it happened to me once with my webcam and another time with my wireless adapter.

Have you tried installing the latest Bluetooth driver for your model notebook from the notebook's manufacturer's website?

Yes, I've tried this. The manufacturer's driver gets stuck during installation not finding any bluetooth hardware.