The product distribution file could not be verified. It may be damaged or was not signed.

Try starting in safe mode; turn virus barrier off -start app store... after this I'm out of ideas.. different things work for different people apparently-- one person reloaded Lion thru recovery and that worked for them... very frustrating. Wish you the best.

Canyonlight-- make sure your turning Virus Barrier off in preferences and not just closing it.... I think its "preferences-Advanced" then hit off.

The virus barrier + deleting 'c' in the the /vr/folder worked. Good find .

Same problem with a few apps.

For Anyone who knows what it means this is what the console tells me when I get this error!

29/07/2012 16:58:48.174 App Store: *** Assertion failure in -[ISDistributionManager verifyDistributionAtURL:allowsDevSign:error:distributionController:], /SourceCache/Pisa/Pisa-93.7/Source/ISDistributionManager.m:147

29/07/2012 16:58:48.175 App Store: FRPurchaseManager: Preflight operation for 537386512 failed with error: Error Domain=com.apple.appstore Code=0 "The product distribution file could not be verified. It may be damaged or was not signed." UserInfo=0x7fee88ebefd0 {NSLocalizedFailureReason=Cannot create PKProduct from "file://localhost/var/folders/p7/pk6fptx1103c8bhg75t0jh480000gp/C/com.apple.app store/537386512/preflight.pfpkg" Error Domain=NSURLErrorDomain Code=-1100 "The requested URL was not found on this server." UserInfo=0x7fee88ecc150 {NSUnderlyingError=0x7fee8a413380 "The requested URL was not found on this server.", NSErrorFailingURLStringKey=file:///var/folders/p7/pk6fptx1103c8bhg75t0jh480000g p/C/com.apple.appstore/537386512/preflight.pfpkg/index.sproduct, NSErrorFailingURLKey=file:///var/folders/p7/pk6fptx1103c8bhg75t0jh480000gp/C/co m.apple.appstore/537386512/preflight.pfpkg/index.sproduct, NSLocalizedDescription=The requested URL was not found on this server.}, NSLocalizedDescription=The product distribution file could not be verified. It may be damaged or was not signed., NSUnderlyingError=0x7fee88ed4c70 "The requested URL was not found on this server."}

29/07/2012 16:58:59.886 com.apple.launchd: (com.caleido.portmap[1245]) posix_spawn("/usr/sbin/portmap", ...): No such file or directory

29/07/2012 16:58:59.887 com.apple.launchd: (com.caleido.portmap[1245]) Exited with code: 1

29/07/2012 16:58:59.887 com.apple.launchd: (com.caleido.portmap) Throttling respawn: Will start in 10 seconds

sKibo-- what is the context.. do you have Mountain Lion installed and are getting this message?? What have tried??? Is this for updates thru store or new downloads?

Used an app called EasyFind to search for com.apple.appstore. Deleted that folder once it was found. Relaunched AppStore and was able to download Mountain Lion once again.

Mountain Lion purchased and loaded fine on MBPro with VirusBarrier running. This is the log of the error I get on the console when the Error in discussion appear during attempt to download Mountain Lion on my iMac.

I also have the same problem same with Posterino on Appstore.

So far I have not deleted the "appstore" file, but have deleted all junk files, cache, etc from appstore on the machine to no avail..

This update improves overall stability, supports general compatibility issues, and addresses a number of other minor issues.

STOP PRESS........VirusBarrier 10.6.17 has just appeared, with the message..............

This version is compatible with OS X Mountain Lion.

Let me clarify my post above. I deleted any and all files and folders that had com.apple.appstore in them. I also have Virus Barrier X6 10.6.17 installed and it didn't seem to make any difference whether or not it was on or off, however, I have had Virus Barrier interfere with the AppStore in the past. Just doesn't seem to make any difference this time.

I am now successfully downloading Mountain Lion

I installed the update for VirusBarrier BUT switched it off in preferences, just in case.

I deleted all files and folders in my "///var/folders/p7/pk6fptx1103c8bhg75t0jh480000gp/C/" folder ( (found from the consol log) then searched in Finder by using "Shift-Command-G", pasted in the above location, then "go" to find the folder and deleted everything. A few files in use had to be "put back".

Mission accomplished

Instead of fighting my Mac I'm going to make a large note to use Console to research the error first. Also need to remember that Virus Barrier is so good it even keeps me from doing things. This wasn't the first time I ran into Virus Barrier stopping me and I bet it won't be the last. Mountain Lion is now downloading thanks to this thread.

Great way to summarize.... thanks. When I left Windows after I retired I had hoped I wouldn't have to delve into the inner workings of any computer... alas life is not like that. But the Apple forum folks share stuff and that makes it work.

Thank you SOOOOO much, you're a lifesaver! It took me a few tries, but once I finally did right it worked like a charm with no restart.

My consol said:

file:///var/folders/tg/1br2m6rn467_7ly1jzyg7hr80000gn/C/com.apple.appstore/537386512/\

And I had to cut it to the bolded part, but once I realized that it worked. Again, thank you so much. I agree with Rebecca and Grey.

One more time, THANK YOU!

two words. SAFE MODE. log your computer into safe mode by holding shift while you turn it on. Release the power button but hold shift until you get to the gray screen with the apple and spinning gear. let go of shift. you will see a progress bar pop up which indicates your loading into safe mode. Safe mode usually take about 2-3 minutes longer to load than your normal boot process, so be patient. Once in safe mode (it will look like your normal desk top) go into mac app store and try to download mt lion again. Guarantee it will work.

And with that being said, you dont have to worry about going into terminal and entering any code which could end up f*ck*ng up your system if your not careful.