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Firefox: The program must close to allow a previous installation attempt to complete


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I was running Firefox under a limited user account, and got the "critical updates needed" icon, which I foolishly pressed. Then I find out it can't install unless I'm an admin, so I log back in as admin, finish the install, and it won't run. Instead Firefox will say "The program must close to allow a previous installation attempt to complete" and then shutdown.

Various combinations of uninstalling firefox, rebooting, cleaning firefox keys from the registry, rebooting, reinstalling firefox still result in the error message "The program must close to allow a previous installation to complete".


Remove the restrictions from that account and try then again (uninstall, fresh install) That worked for me. I had a similar situation where 2 Windows installations shared one machine.

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2006-08-01, 11:56:26
anonymous from Spain  


This error usually happens on interrupted upgrades or power offs, the resolution is very easy you had to go to the program files folder, and after the mozilla folder.

And just delete the XPCLEANUP.DAT file. That´s it.. No more troubles, finito…
And you can enjoy the best browser…
2006-12-02, 04:41:41
anonymous from Belgium  
2007-02-09, 18:46:01
anonymous from Switzerland  
The solution for Vista can be found at xpicleanup.dat is located in the “C:\Users\\AppData\Local\VirtualStore\Program Files\Mozilla Firefox” folder in Vista. Deleting it there seems to work.
2007-02-10, 16:21:36 from Alicante in Comunidad Valenciana, Spain  
I also have vista, and I tried both advice, and still can't run it... should I delete something from C:\Windows\AppPatch, I have nothing under c:\program_files\mozilla firefox or c:\users\myuser\appdata...
2007-04-02, 09:59:56
anonymous from United States  
deleting XPCLEANUP.DAT file worked for me, thanks!
2007-04-19, 17:49:16
anonymous from United States  
worked like a charm!!!
2007-05-16, 07:43:00
I have vista. When I try to delete the xpiclean.dat file it says I need to have permission to delete the file. But i am the adminstrator... heelp.
2007-05-24, 05:54:30
anonymous from Finland  
thanks, worked for me too, delete: XPICLEANUP.DAT
2007-08-21, 10:11:28
anonymous from United States  
If you can't delete the file in Vista you will need to end the xpiclean.dat process in the task mgr. This problem still happens with my machine every couple of weeks though.. Any long term solutions?
2007-10-31, 23:55:24
AlfaLymanBlob from Sweden  
After many attempts I think I finaly worked it out. On vista first check if there are any xpcleanup process running, if so kill them all. Then Deleat that file in mozila folder (xpcleanup). Than right click on firefox icon and run as Admin, firefox will continue to update and work. If that didnt work uninstall and fresh install.
2008-06-13, 08:03:57
anonymous from Bahrain  
thanks, worked for me too, delete: XPICLEANUP.DAT
2008-07-12, 04:37:16
Omar from Egypt  
Thanks guys deleting the xpicleanup.dat file under the firefox folder worked for me, it's nice and easy solution

2008-12-02, 19:21:39
anonymous from Peru  
gracias funciono para mi tambien, borren: XPICLEANUP.DAT de la carpeta Moziila Firefox en Archivos de Programa y se soluciona el problema, yo tengo Windows XP con SP2 y me funciono de maravillas,
2013-10-31, 13:14:21
Grace Yak from Benin  


Greetings my dearest one,my name is Grace YAK am 25 years old Girl
from Southern sudan.I want to have a common relationship with you, I
need to tell you more things, but first I need your help to Stand for
me as a trustee. My father Dr. Justin YAK Arop was the former Minister
for SPLA Affairs and Special Adviser to President Salva Kiir of South
Sudan for Decentralization. My father Dr. Justin YAK, my mother
including other top Military officers and top government officials
where on board when the plane crashed on Friday May 02, 2008. You can
read more about the crash through the below site: Some months after the
burial of my father, my uncle conspired with my step mother and sold
my father's properties to a Chinese

Expatriate. On a faithful morning I opened my father's briefcase and
found out document which my beloved late father used and deposit money
in a Bank in Benin Republic, with my name as the next of kin. I
travelled to Benin Republic to withdraw the money so that I can start
a better life and take care of myself. The Branch manager of the Bank
whom I met in person told me that my present status does not permit me
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the money or I should wait till when I will get married it demand by
their Authority......... I have chosen to contact you after my prayers
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soon revealing myself.

to you without knowing you, well, I will say that my mind convinced me
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You will also help me to place the money in a more profitable business
venture in your Country.

I am writing this email to you with the private office computer of
the coordinator in charge of the refugee camp where I leave now, his
name is Rev. Father DAVID FRANK of sacred hearth Catholic Church Benin
Republic However, you will help by recommending a nice University in
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compensate you with 20% of the total money for your services and the
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message indicating your ability and willingness to handle this
transaction sincerely. Please do keep this only to your self. I beg
you not to disclose it till i come over because I am afraid of my
wicked uncle who has threatened to kill me.

Please contact me through my private email address as below (

Sincerely yours
Grace Yak

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