Adobe Reader error "Could not find Acrobat External Window Handler"

I cannot open any .pdf files.  When I try to open a .pdf file in the Web browser it gives me an error message "Could not find Acrobat External Window Handler".  When I try to open a pdf file directly in Acrobat Reader it gives me an error message saying "There was an error opening this document.  A temporary file could not be opened."  I already tried uninstalling and completely cleaning out Adobe and then reinstalling it but it did not work.  I am using Adobe Acrobat Reader 5.0 on Windows 2000 Pro.  We are on a Microsoft Exchange Server 2000 if that matters. I tried some of the solutions on the Adobe website for this problem however they did not work.
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Reader creates temp files which it is supposed to clean up after itself. it has a bug and sometimes creates 64000 temp files and then can't open since it has run out of numbers to assign to new tmp files. Problem was solved by going to CMD prompt in the temp directory (<userhome>/Local Settings/Temp), then del acr*.tmp.

This is apparently a fairly common problem for Adobe's tech support people to get. Apparently you can refer to document #329444 on their tech support site- not exactly this solution, but the idea. (i haven't looked but was given this reference.)

Credit: Solution posted by jklugmn on C|Net

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
I want to thank gprellwitz for posting the above answer.
I spent several hours on Thursday trying to solve the same problem.
Didn't know where adobe put the temp files. ( duh ! )
Searched this site and the web for two hours and found nothing 'cept for this question with the previous useless adobe link.
You'd think frickin Adobe would mention that little gem on their main support
link for the "external windows handler" problem .... as opposed to "reinstall the operating system and only acrobat and see if it works" !
I'll be hating Adobe for a long time for their crappy support site.
Kudos and Mahalos again for the answer !
You deserve a lot of points and may I suggest this question gets left on the site for
a long long time since there is very little cogent material on the web referencing this problem.
Bootstrap 4: Exploring New Features

Learn how to use and navigate the new features included in Bootstrap 4, the most popular HTML, CSS, and JavaScript framework for developing responsive, mobile-first websites.

gprellwitz YOU ROCK!!!

I did numerous web searches (adobe, google, altavista, no answer or not the solution uninstalled acrobat 5 and 6 probably 2 or 3 times at least/each. I had 66,296 objects in Temp did the delete and cut that down to 763 - pdfs open with no error in Acrobat reader AND in web browser.

Thanks a million.

To me this only occure with IE6. with other browsers  : Mozilla, Opera. Thunderbird is OK.

Any way the problem still is there even after try the solution gave in the top of the forum.
The fact that it only occurs with a single browser seems to indicate that it ISN'T the same problem, though it certainly wouldn't hurt to delete the extra temporary files anyways.  Sounds more like the association between IE6/Windows and .PDF files is broken.  Given your familiarity with non-IE browsers, however, I would guess you've already thought of that.  Re-installing Acrobat Reader should go through and reset the associations, but again, I presume you've already tried that.  Which of the error messages given at the start of the thread are you getting?  What happens when you try to start Reader in standalone mode?

I repaired The Acrobat and  the error persist . So only with  a reinstall I thought to clean the anomaly, but wrong. As before with Mozilla, Thunderbird, Opera 7 it works well. With IE6 and a new browser MyIE2 the error is the same. Acrobat starts and crash waitting to read pdf web page and after the  message " Could not find ........".

It works if I efface in preferences. Internet, Display PDF in Browser, in Acrobat Reader.

That's all. This bug remain since I begin to use the new Acrobate 6.0 or with last IE6 patchs.

Hello again,

I have Acrobate working fine with IE6.

Last 20th December I done some updates in XP from Microsoft portuguese site ( KB824145 for Internet Explorer 6 SP1) KB824146, KB824141 (security patches) KB8826939 (for Windows).

After the reboot I red lot of documents in PDF and saved and emailed some of them. I must think the reason is engaged with old configuration and the new had from the update.

If not so reply.
Merry Christmas to All People

Deleteing the acr*.tmp also allowed Acrobat 6.0 to run. I suddnely started having problems as described by many that Acrobat reader 6.0 seems to be chewing up CPU and just plain hanging up. Deleting the acr*.tmp files cured the problem and to think that I spent a full day just trying to find a solution to this problem.

thanks for the tip
If all people agree its time to close. Now I work with last release, french version, and all troubles are gone.

Thanks to all experts.

Thank you, Thank you, Thank you,, I worked for days, pulling my hair out, uninstalling, re-installing, going from 6.0 back to 5.0 and even 4.0. Of course nothin worked until I found the answer above. Takes a while to delete 64000 files but not as long as it took to find out that that was the problem. Somebody needs to get this info over to the Adobe troublshooting page.  Thanx again. Back to 6.0 and up and running again...:)
How do I execute the accepted answer in Windows XP?  I don't think I have a foldeer called "local settings."  How do I get the command interface to point to the right folder. Thanks.
Woo, just had this problem occur.  65,535 tmp files.  Sheesh.  Taking 10+ minutes just to delete them.
I got this error message when I upgraded to Adobe Reader 7.  I had no .tmp files to clean up.  It turned out that the upgraded nppdf32.dll needed to be copied into my \Netscape\Communicator\Program\Plugins folder.  For reasons I can't explain here I am still running Netscrape 4.7
For Windows XP by default the local settings folder is hidden. Go under tools, folder options click the view tab and you will see it.
I have windows 2000 professional, and acrobat 7.x reader,  i am not able to open pdf files in internet explorer . I only get a small box with a red cross in it on the webpage.

kindly help where the problem lies

regards and thanks


It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Adobe Acrobat

From novice to tech pro — start learning today.