The .exe extension on a filename indicates an executable file. Executable files may, in some cases, harm your computer. Therefore, please read below to decide for yourself whether the BtTray.exe on your computer is a Trojan that you should remove, or whether it is a file belonging to the Windows operating system or to a trusted application.
The process known as Bluetooth Tray Application or Bluetooth Application or WIDCOMM Bluetooth Software or BlueSoleil Bttray or Lenovo Bluetooth with Enhanced Data Rate Software
belongs to software WIDCOMM Bluetooth Software or HP Integrated Module with or Bluetooth Software (version 1.4.3 Build 4, 1.4.2 Build 10, 1.4.3 Build 3, 3.0.1 Build 3, 1.4.2 Build 18, 1.4.1 Build 4, 1.4.2 Build 19 SP1, 1.4.1 Build 6) or Belkin Bluetooth Software or HP Integrated Module with Bluetooth wireless or ThinkPad Bluetooth with or Lenovo Bluetooth with or Ralink Bluetooth Stack64 or IOGEAR Bluetooth Software or Dell Bluetooth Software or Broadcom Bluetooth Software or Sitecom Bluetooth Software or Bttray Application or Qualcomm Atheros Bluetooth Suite or Lenovo Bluetooth with Enhanced Data Rate or Targus Bluetooth Adapter or D-Link Bluetooth Software or Broadcom (version 2070 Bluetooth 2.1 + EDR) or Fujitsu Siemens Computers
by Broadcom (www.broadcom.com) or WIDCOMM (www.widcomm.com) or IVT (www.ivtcorporation.com) or Qualcomm Atheros.
Description: BtTray.exe is not essential for the Windows OS and causes relatively few problems. BtTray.exe is located in a subfolder of "C:\Program Files" or sometimes in a subfolder of C:\ or in C:\.
Known file sizes on Windows 8/7/XP are 581,693 bytes (15% of all occurrences), 577,597 bytes and 96 more variants.
There is an icon for this program on the taskbar next to the clock. BtTray.exe is not a Windows system file. The process can be removed using the Control Panel's Add\Remove programs applet. BtTray.exe is able to record keyboard inputs. BtTray.exe is able to monitor applications. Therefore the technical security rating is 51% dangerous, however you should also read the user reviews.
You can ask Customer Support  to assist you, update  the program or uninstall the associated program (Start > Control Panel > Add/Remove programs > WIDCOMM Bluetooth Software or HP Integrated Module with Bluetooth Wireless Technology).
Recommended: Identify BtTray.exe related errors
External information from Paul Collins:
Important: Some malware camouflages itself as BtTray.exe, particularly when located in the C:\Windows or C:\Windows\System32 folder. Therefore, you should check the BtTray.exe process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.
A clean and tidy computer is the key requirement for avoiding problems with BtTray. This means running a scan for malware, cleaning your hard drive using cleanmgr and sfc /scannow, uninstalling programs that you no longer need, checking for Autostart programs (using msconfig) and enabling Windows' Automatic Update. Always remember to perform periodic backups, or at least to set restore points.
Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off doing a repair of your installation, or in the case of Windows 8, executing the DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.
To help you analyze the BtTray.exe process on your computer, the following programs have proven to be helpful: Security Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. Malwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.