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High CPU usage or Explorer hangs making thumbnails

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High CPU usage.

You have a file (or files) that is causing MysticThumbs to run a process (usually rundll.exe or Explorer.exe) at 100% that never seems to quit, OR Explorer crashes when opening specific folders to view.


Some files are written differently by various applications and sometimes there are also other parts written into files that are not handled well when parsing the file. This can lead to erroneous problems like crashes or processes getting stuck when trying to decode them.


Any number of variations on files or even half written files from applications crashing when writing can cause files to be internally different from the format specification that MysticThumbs expects in order to decode and display the file.



In order to track down what files are causing problems follow the following steps to try to pinpoint the specific file format/extension and possibly the specific files themselves.


Method 1 - Using the tray application

1.Think about which folders are causing problems specifically and check which file formats are in those folders. The folders to look for are ones you just opened when you get a 100% CPU task or Explorer hanging green loading bar or crash when opening.

2.Make sure the tray / notification application is open and visible using the control panel.

3.Whilst the Explorer window is hanging with a green bar, or after it crashed, hover the mouse over the MysticThumbs tray icon. You should get a recent files tool tip. The first file in the list should be the last file that MysticThumbs attempted to thumbnail. Close the Explorer window if required and then try disabling the file type for that file in the control panel. Then open the Explorer folder again and see if it helped.

4.Optional: You can then send the potential problem file(s) attached to a support request to us to investigate and optionally move it to another folder that you are not going to use for safe keeping to prevent the problem for the time being; then re-enable the file type in the control panel if you really need it.


Method 2 - Using Disable all and Selective file format enabling

1.Close all Explorer folder windows and all open applications.

2.Disable all file formats thumbnails and small icons and apply.

3.Enable just one file format you decided on in step 1 thumbnail mode only and apply.

4.Open a folder with possible problematic files / formats in it and see if the problem persists or the folder generates and displays files normally.

5.If there is a problem with the folder opening and displaying files, and you get a 100% task, this folder likely has a problem file.


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