Sunday 15 September 2013

svchost.exe 100% CPU when using Windows Update

Here is the situation: PC dating back to around 2003 running Windows XP SP2 in need of general clear-out and tune-up with all software to be updated. Automatic updates were not working and using Windows Update online would not work at all. Had to download standalone installation of SP3 and install, which all went smoothly. Using online Windows Update now seems compatible, but PC becomes unresponsive and process svchost.exe found to be using 100% CPU. Looking for help online I only found old patches that are included in SP3 anyway. Time to get inventive! Using my trusty old copy of Dialafix tried clearing out Software Distribution folder, but preserving DataStore.edb (update history). That did not resolve the problem. Once again using Dialafix cleared out DataStore.edb as well. Problem solved. The only data lost in this exercise was the Windows update history, which is nothing to cry about! It simply means that Windows Update will have to rebuild that file next time that updates are applied.

Friday 5 July 2013

utorrent upgrade resets port settings

A number of people have just upgraded their utorrent installation to the latest version. Now quite a lot of people I know deliberately tweak various settings to avoid the use of the torrent protocol being detected by their isp. One of the techniques used is to set the outgoing port range to something unusual that their isp does not normally associate with the use of the torrent protocol so as to avoid "traffic shaping" which might slow down their connection. Be aware that the latest utorrent upgrade resets net.outgoing_port and net.outgoing_max_port to zero, totally defeating the tweaks people may have made before. Why? Don't ask me - stupid stupid stupid and why oh why oh why. If you can actually remember what you set these to before the upgrade (you DID document it didn't you?) you will have to set them again before your isp cottons on and degrades your p2p bandwidth.

Tuesday 12 March 2013

uTorrent Will Not Restart

User reported that uTorrent would not run after having closed the program to restart it. A message pops up saying that an instance of uTorrent is already running. This is normal behaviour of the program. uTorrent creates numerous network connections that can take at least two minutes to close after the program has been  stopped, so there is an interval required for these connections to time-out before the uTorrent process disappears from the system (as displayed using Task Manager). This can be verified by using TCPView to monitor the network connections.

Always allow a minimum of two minutes to elapse after closing uTorrent before attempting to start it up again. Failing to do this can (and frequently does) cause a lock-up condition where uTorrent will never fully close down and a system reboot is required to clear the "stuck" process from the system.

Old hands familiar with the DEC VMS operating system will probably remember the dreaded RWAST process state - it is a bit like that old chestnut.

Windows 7 hung at Logging Off phase

This problem would arise when attempting to shut down the PC. Most times it would hang while displaying the message "Logging Off" or on occasion it would get past that and then hang while displaying the message "Shutting Down". Investigation showed that the cause was a well-known one, namely an external USB disk drive connected to the system. These are often the source of Windows shutdown hangs and the correct procedure is to "Safely Disconnect Hardware", then power-off the external disk drive before attempting a shutdown. While it is possible to write a script which performs the "Safely Disconnect Hardware" during log-off and/or shutdown, the power-off still needs to be done manually. If the external USB disk drive is not powered down, it can also cause the PC to hang during the boot sequence when the BIOS attempts to configure USB ports.

Wednesday 6 March 2013

Internet Browsers Not Connecting to Network

This problem arose after a small batch of Windows Updates had been applied as routine operations. Any internet browser program e.g. IE, Chrome, Firefox, Opera would report "Network Unavailable". Unable to connect to the router on 192.168.1.1 using a browser either. Other network programs e.g. FTP, uTorrent, ping to router and ping to google.com all working ok so it was not a generic network connectivity promlem. This had to be something specific to the HTTP protocol. Symptom consistent with blocking of tcp port 80 so inspected Windows Firewall rules for any anomaly - none found. Temporarily disabled firewall (unplugged DSL connection first for safety due to reasonable paranoia about such things) and problem persisted, so this eliminated any issue with the firewall. Malware scans all clean. Rebooting did not clear the problem. Used System Restore to roll-back to the time just before the Windows Updates had been applied and this cleared the problem. Reapplied updates manually and no problem apparent after that. I did not "get to the bottom" of this one, but the fix using System Restore worked well enough! The System Restore utility is truly a life-saver at times.

Friday 1 March 2013

Windows 7 Recycle Bin stuck not emptying

Curious problem today noticed when using CCleaner. The cleaner program hung while trying to empty the system recycle bin. Killed off the CCleaner program and tried manual emptying of recycle bin, which did not respond. Opened cmd window as administrator and tried command rd /s /q {drive letter}:\$Recycle.bin on each drive in turn. This command hung when tried on drive Y: so killed cmd window. Tried running Explorer and selecting drive Y: which then hung. Killed Explorer window and rebooted. Tried running Explorer again and selected Y: which was ok this time. Folder found called RECYCLER. Deleted that. Also found same folder name on drive Z: so deleted that. Recycle bin working correctly now. All disk drives now show folder named $Recycle.bin in their root directory.

Drives Y: and Z: are external USB drives that used to be connected to a Windows XP machine so the name of the folder associated with the recycle bin is different to that now used for Windows 7. It just so happened that one file had just been deleted from drive Y: and this was the first file to be deleted since it had been connected to the Windows 7 machine several months earlier.

My conclusion is that when connecting an external drive to a Windows 7 machine where that drive has been used on earlier versions of Windows, it is a good idea to delete the folder RECYCLER in the root directory to prevent any problems with the future use of the recycle bin.

Saturday 23 February 2013

UDP Torrent Trackers Connection Timed Out

Following the most recent update to uTorrent (version 3.3 build 29126) it was noticed that there was a problem with UDP trackers reporting a status of "Connection timed out" most of the time. Manually forcing an "Update Tracker" sometimes cured the problem but became very tedious to maintain. Investigations eliminated a problem with some of the trackers actually being offline temporarily, After a bit of tweaking, the fix proved to be quite simple. Open uTorrent and select menu item "Options" and then "Preferences".  Under the "Advanced" section, scroll down to find parameter "bt.trans_disposition". Change the value of this parameter (which was set to 31) to the value 15, effectively switching off support for the new uTP header which is not backwards-compatible with older protocol handlers. Restart uTorrent. Problem solved.

It seems that the installation of the uTorrent update resets the value of parameter bt.trans_disposition, since I had previously set this to 15 on earlier advice.