Sunday, December 22, 2013

How to fix flash player crashes in Firefox by deleting certain prefetch files

In attempt to find a solution to the flash player constantly crashing Mozilla Firefox, I believe I have come up with a solution for some users. As you know flash player crashes within Mozilla Firefox are overwhelmingly common, and nobody is attempting to think outside the box for a solution. I have found two solutions that I can confirm will work for users experiencing crashing after using Firefox and flash player for a period of time. This fix will NOT work for everyone. Users experiencing crash upon start for Firefox and flash player will not most likely work for that issue, but please feel free to try. 
Get Adobe flash player here . Please be sure to UNCHECK the McAfee as that is just additional BLOAT in my opinion.

Keep selected prefetch files clear:
The first solution I came up with involves creation of a task in windows 7/8 that upon regular intervals deletes some prefetch files in the windows prefetch directory. This was my method that I used to solve my flash player crashes in Firefox and have used it successfully since mid 2013. I have created a shareable folder with some automated scripts, a readme file, and an undo bat file (to remove my scripts) to assist in the proper creation of the task, and the necessary files to perform the deletion of the 3 prefetch files. There are two exe for this, both do the same thing. One is created in WINRAR SFX EXE and the other in AUTOIT either will work. Those links to the complete folder will be at the bottom of my page with the Info version of it which you should read first. 

Direct links to first (winrar exe ) and second (autoIT installer Updated 2/3/2014 ) ones for quick reference.

July 22 2016 - UPDATE:

I will not be currently supporting this method anymore. No future development.
If you are having plugin crashes, I suggest that you use the 64 bit version of Mozilla Firefox as it is much more stable than the 32 bit versions of it. Of course if you are one of the many unfortunate people with a 32 bit operating system, then maybe it is time to move into the modern day of technology. 64 bit systems have been around for over 7 years, and started to become popular after the windows 7 release in 2009. 

August 16 2014 - UPDATE:

1) 64 bit version update ONLY 1.4 here ( its already checked, hit the download button at the top). I will only be programming for 64 bit windows only going forward. The code has been added on github. the link is a few lines down in the highlighted section
2) I added some logic in the installer to create a folder structure withing the 'programdata/scripts' folder as i will be using the scripts folder for more projects
3) Added some conditional if statements into the installer to verify the install of the files and task 
4) Changed the xml file to reflect the changes in 1 above.

 September 14th  2014 - UPDATE:

This will most likely be my last update in this series as I found a simply way to do this without creating a windows task to run this every 5 minutes, and it was so simple to do.

1) 64 bit version 2.0 only. 
2) This is an exe that you double click, or place in the windows start up folder. This will delete prefetch files as they are created; well every 30 seconds. This is a low resource exe and should not hinder your CPU.
3) will show as a red cross in the system tray. 

This is based off the actual exe that does the deleting of the prefetch files in my original iteration, with the program running in a infinite loop and using ' IF THEN ' statements to confirm the existence of said files and if so deleting them.

The files in the prefetch that are deleted are: 

The download for the V2.0 file is here. Simply click the download button at the top as it is already checked for you.

December 27 2014 UPDATE: 

To those of you who would like to test this out in a bat file format, i created a BAT file so YOU can see the code as I get harassment from Mozilla Forum moderators about my creative thinking and refuse to even consider these solutions, let alone test them. Talk about incompetence!  Once or IF you n't want to see the CMD window all the time, you can grab the exe, or the source code and compile it yourself if you as paranoid as they are. 

Feel free to to test/submit any of my code at or wherever to really see if it is malicious

Download the BAT file here

June 12 2015 UPDATE: 

Updated the Auto Delete version to 2.5 to include less CPU usage by about 30%, the icon in the system try will display green if it has not deleted anything, and will turn to a red cross if something was deleted. NO tool tip. Removed the pause/exit script if you click on it and put an about/exit instead.

Version 2.5 can be found here


1) go to this page: 

Flash clean up and re-install

2) Read it, and determine which method you choose to use

3) You can use the exe file listed in the September update above or the BAT file in the most recent update.

4) Simply double click and run 


You can stop it anytime by going to the system tray clicking on the red cross icon, and choose Exit. 
NOTE: the script will pause once you click it, and you have to hit pause again to get it to stop flashing ' pause '. 

I will put up another version with a 'hot key set ' to stop it as well in the near future.

The code can be found here


IMPORTANT NOTE: IF you use full screen gaming, then you must use the second link ( right above this sentense) for the one written in AUTOIT, as a compiled exe does the deletions. as you will be booted from fullscreen mode b/c of the .vbs script that does the deletions in the first link. 

This Will also not work on computers attached to a domain. it will error out 
The version V2.0 will work as it does not create a task.

The code for all the AutoBeta installer and associated files is located here

It is important to note, that now the source code is available I will be only making updates to the 2FireFox-Flash-Fix(x86)_autoBeta installers. 
The 1Firefox_1Flash_FIX(x86) version will remain available but any additions or code modifications will not be done to it.

I would like to point out that a thread was started called:

"Proposed new solution to some FlashPlayer problems”

In the Mozilla forums which involved contributors and moderators. Needless to say the moderators and contributors refused to do any testing of my proposed solution. As the vast majority of users want a click and fix solution, and do not want to sit and fiddle with code, and do things they cannot understand because they are not computer literate. I offer at the bottom of page a few links to Mozilla forums where proof of my methods can resolve these issues.

Flash player protected mode: Automated script to disable protected mode for flash player

Disable plugin container in an attempt to resolve the flash player crashes if clearing prefetch files do not work.(Mozilla recently broke this method of disabling the plugin-container)

I would like to give a special thanks to the following Mozilla forum members for assisting me in confirming my testing and willing to try my methods:





Also thanks to Adobe forum member Troudhyl. Even though either method or various other methods we tried didn’t work for his flash player crash upon startup of some links, this helped me to confirm what it didn’t resolve for sure.

Below is the link for the folder with the proposed fixes, and please be sure to read the info.txt file prior please. You will need winrar to open the archive files.

YouTube tutorial

Please note that i can provide limited technical support for these. There is the info word document available to read. I tried to make this a simple as possible. Please be sure to read these.

Best Regards to all


Here are some links to my proven cases of persons who have tried my methods:



Be sure to Check out my other post for complete uninstall, clean up of all flash files, and re-install from a script.



  1. I've been using your clear prefetch task (props for it btw it works!) but I've noticed a problem.
    Every time the task triggers your .vbs script, I get tabbed-out of fullscreen (whether it's a game, a movie, or the screensaver).

    I'm thinking the objStartup.SpawnInstance_ might be tabbing me out, but I'm not at all versed in vbscript to know what to do about it. All I could do is make it show a normal window (5) instead of a hidden window (12) to verify that it's your task that's causing the problem.
    Any thoughts?


    1. Tudor, i can confirm that the vbs script does minimize out of full screen modes. IF you use the one called: 2FireFox-Flash-Fix(x86)_autoBeta from the list in my folder ( link above ) this uses a different way to preform the delete ( its actually a compiled exe file written in autoIT).
      The 2FireFox-Flash-Fix(x86)_autoBeta will remove all instances of the previous script and install the exe one. THis one is completely silent except for the cmd window.

      I can confirm that this should not minimize full screen games as this was the original one i created. The reason the one you are using is b/c of a bunch of cry baby moderators in the Firefox forums was making accusations that it was an exe file. That is what prompted me to provide you with the code to create your own exe that does the deletions of prefetch

      I did provide the code for this in the folder called 'misc' in the above folder i have a link for ( prefetchinstaller.au3 ) MINUS the payloads so anyone can see the code ) .

      The code for the actual exe that does the deletions is called del_flash_prefetch.au3 in AutoIT.

      I also provided a 'delete if exist.exe' that will sit in your system try and delete files as they are created in the prefetch, all you have to do is add to start up items. It shows as a red cross in yous system tray. DO NOT CREATE A TASK FOR THIS as it does not need it.

      Best Regards

    2. Oh, I see. Thanks! Code looks legit. :)
      To shut the moderators up, if you feel like it, you could make a small github with the source, and instructions on compiling it; then just link them to that instead of the exe. That's what you'd do in linux anyway.

  2. thanks for info- deleting the files you mentioned worked for me

  3. I'm going to give this a try and will report here on the results in a few days. I'm curious, in what way exactly does deleting the specific Prefetch files affect Firefox/Flash functionality? [i.e. What is the causal chain?]

  4. All i know about prefetch files is they contain data to assist in faster start of programs. As a result when either Firefox, plugin container of flash player are called up, it references this plugin file, and my speculation is that there is bad/corrupt data in it in some way that causes the crash. Even though this deletes several .pf files my money is on the plugin-container.exe pf file that is the culprit.

    So when it is not there( the prefetch file ), when plugin container is called, there is no prefetch file to reference, resulting in no crash. This is my only logical theory

  5. This comment has been removed by the author.

  6. 1Firefox_Flash_FIX(x86).exe did the trick for me. Thanks for that.

  7. Carm, I thank you. My wife thanks you. My little children thank you. You are a genius. Srsly, thank you.

  8. Hi Carm,
    I came across your thread in the Firefox forum. I have a new Win 7 (64bit) notebook. When I watch (for example), the flash player does play, but the control to enlarge the viewing to "full" is gone. When I right-click, the plugin crashes. I get the "Shockwave Flash may be busy, or it may have stopped responding..." message. I've now spent 3 days trying to get answers. Since I'm not a tech person, I'd like to know if you have a step-by-step instruction you can share with me.
    Thanks much! - Richard

  9. Richard,

    There are a couple alternatives to try, the one on this blog you commented on is by far the simplest to try, it is the most up to date one that I have modified, the other ones are as is.

    Please make sure you read the posts carefully.

    Sorry if this post is lengthy.

    Before you do anything remember that I cant guarantee this will work for you or not, as this is a weird issue and some people it will work for others it does not do crap.

    FIRST: I recommend a FULL uninstall, and that cannot be done at the control panel. I have another post addressing that here:

    This will uninstall, and download the latest version 15 flashplayers for IE and Firefox ( it will force close all browsers ) , then it will delete some left over flash player files then re-install the latest v 15 flash players. Once adobe changes to V16 in the future this WILL NOT get the latest as the download link changes. There are of course manual instructions and the source code.

    There is an V15exe at the bottom to automatically do this for you.

    Simply scroll up to the text in this blog: September 14th 2014 - UPDATE:

    There is a link to V2.0. That will open a page with a bunch of files in it. Since i coded the link to automatically choose the latest one, go to the top bar and press download.

    This is a compiled exe. The source code link for that is below. I placed that there because of the mistrust due to viruses etc. so people can submit the file etc...

    It is a red cross icon. simply double click it, you will see it running in your system tray by the clock. to end it you can just click and choose exit. its by far the simplest of the versions of this method.

    This is the one a recommend the most.

    I hope this helps. I do have videos for the older versions that are very detailed, but they are for the older versions of this, as I have not had a chance to re-make them for the newest one that does not involve in creating a windows task.

  10. Great work! I like this post and i feel very happy to read this article... thanks for sharing... visit- Mozilla Firefox support Toll Free No +1-800-231-4635 For US/CA.

  11. I just tried it and it opens up correctly. Make sure you have the latest version of winrar... thanks for sharing visit- Mozilla Firefox help.