I must apologize for neglecting to post the resolution to our problem (about the Macs receiving corrupted Software Updates or any other DL's from the Web or eMail attachments).

The ISP sent his crew and swapped out his router. That resolved the problem. We never were able to determine exactly what—inside the router—went bad, but the new router (same brand and model but can't remember which) fixed everything.

Yes, all the PC had NO problems; something in the bad router only screwed up attachments/downloads/software-updates for the Macs only.

Thanks for coming back on that, I really do wonder what was wrong with the first router. I'd say 99% of the time there is no networking problems with my Mac, but I have been on three networks where this has happened, and I have no idea what causes it. All my Mac network settings are correct, but I cannot download files/attachments/software update properly. All the PCs on the network have no problem. At one time our network guy actually set one of the local PCs up as a proxy, and I pointed my Mac at that machine. It was slow but worked.

My home case with the satellite is the same as the thread. Downloaded files all have 'codec overrun' when I try to open the DMG file. Software update comes up with a similar problem. I will check small zip files, I haven't really checked that (most files are DMG files, anyway). It is compounded because the local ISP has no clue about Macs, so are not helpful (no offense to them, since this is a really strange problem). I wish someone with good networking experience could help me to debug it. As it is, I just download all files/updates at work, then take my Tibook home and copy over the files. Not a good solution.

Some things to try:
- check that the downloaded DMG (or other file) has the correct size. (Sometimes the size in bytes is listed on the download site, otherwise you might need to download it elsewhere just to check the size)
I suspect that the problems you are having occur when a download is truncated - e.g. when the server disconnects before it is finished.

- try downloading via the 'curl' command-line program.
E.g. (in the Terminal):
curl -o mydownload.dat URL_of_file_to_download
where you would replace "URL_of_file_to_download" with the actual URL (e.g. obtained via copy & paste from Safari)
and where "mydownload.dat" is the name of the file where you want the contents of the download to be stored. (It can be anything you want - usually you would specify this to match the name used in the URL)

sanook

it sounds to me like you HAVE someone with good networking experience trying to help solve your problems. troubleshooting computer problems is pure algebra... you have to eliminate the variables. you should try what he suggested, as it is a *key* variable in this equation. if that doesnt turn anything up... im sure hayne, and anyone else with experience in networking, myself included, will be able to give you a more eduacated attempt at a solution.

i dont mean to come off condecending or negative at all, but haynes got a good idea...

hi five bro

Thanks for the responses, everyone. Much appreciated. Once I get home tonight I'll test curl. Obviously wont work for SU, but if I can get large DMG files to work I'll be happy.

Again, no offense intended at all, I appreciate the help! :o

Bump! "Codec Overrun" and "Invalid Checksum" errors
 

Hi,

This thread is the most similar to the problem I've been having.

Since I started my new job in Jan and have been using a mac for the first time in years I've had problems downloading things.

A few months ago when I finally updated to 10.4.9 I had problems downloading that until I repaired disk permissions and cleaned the cache, when the update came down fine.

Since then everything I've tried to download including all other mac updates - itunes, iphoto, quicktime etc; Firefox, Aquisition, Silverfast and Vuescan (trying to fix another issue with a scanner) all have verification failure upon downloading. When trying to mount I was first getting "invalid checksum" then "codec overrun", and then today invalid checksum again.

the only thing that has come down was the 10.4.10 update which came down first try with no errors.

I've tried several things from several threads I've found.

I've tried resolving disk, permission and cache corruption with Disk Utility and Cocktail.
I've deleted extensions.kextcache, mkext, and com.apple.kernelcaches.
I tried the curl command as stated in this thread, but am not sure if I did it right.

Some suggestions in this thread I don't quite follow...

My ISP is cable and I just tried connecting the ethernet direct to the computer without going through the router and can't get a internet connection. don't know why...

Might this be a router problem?

I'm going to try a download from another mac and see if I can mount a file from disk.

Is there anything else I can do? Should I try a different router?

any help would be much appreciated. Even if I get this file to mount from disk it doens't fix the problem of not being able to download direct to this comp.

thanks in Advance

btw...running 10.4.10 on an iMac6,1 2.33 GHz Intel Core 2 Duo

&uotconchdoggy:

Did you ever find an answer to this? I am experiencing the same issue...every download is corrupted and it just recently started happening. It was running fine at first (downloaded all types of files successfully) but after updating to 10.4.10, I started experiencing this issue...

Anyone else?

- Scott

You should try the standard troubleshooting suggestions:
http://www.apple.com/support/mac101/ (see the "My Mac needs help" section)
http://www.macosxhints.com/article.p...04011205473937
http://forums.osxfaq.com/viewtopic.php?t=7269
http://www.thexlab.com/faqs/faqs.html

In particular, be sure to try logging in as a different user to see if the problem exists there. (Create a new user via the Accounts preference panel if you only have the one user account so far.)

Also be sure to do "Repair Disk" (different from "Repair Disk Permissions"!) in Disk Utility when booted from the Install CD/DVD. I.e. you restart from the Install CD/DVD, then run the version of Disk Utility that is available from one of the menus there.
See this Apple doc:
http://docs.info.apple.com/article.html?artnum=106214

My solution was to swap out the router. I can't begin to list all of the issues I've experienced with routers gone bad. The latest was a periodic lack of Internet access that I was blaming on my cable company; they are an easy target, after all. The problem got so bad that I had even connected both the cable modem and router to a separate power bar so it would be easy for my wife (a non-techie) to know what switch to flip off then on when the problem would occur while I was out of the house. Finally tried resetting the power just on the router and found that that was the culprit. That was the fifth or sixth router I've bought in the last eight years. I've gone through Linksys, Netgear, and Dlink. Dlink products absolutely suck. Netgear routers are mostly okay but I've seen them fail more often than the Linksys routers.

I'm now on DSL and am using the wireless gateway from AT&T; so far it's working well but we'll see if I made a mistake combining both modem and router into one device. At least, during the warranty period, I can point my finger at one vendor if there's an issue. :rolleyes:

Codec Overrun Error
 

Hi,

I have just got broadband, and my iMac G5 Intel (OS 10.4.7) was just fine with the downloads. No Codec Overrun errors at all. I downloaded Google Earth, Skype, all .dmg files and had no problem.

I then did a software update and the problems began!

I did a Firmware update, maybe that is causing the problem, but now I cannot download ANY .dmg files without a Verification failed error and the a Codec Overrun error.

I am reinstalling my whole system - will let you know how this goes.

Does Apple have any comments on this problem???

I FOUND the cause on my Mac!!
 

:D

After re-installing and taking notes of what was happening on my machine, I think I found the problem!!

When I share my Ethernet internet connection via my Airport connection with other machines (in this case my husbands PC), the .dmg downloaded files start giving verification and CODEC OVERRUN errors.

If I go to System Preferences - Sharing - Internet and stop the Internet Sharing, the .dmg downloads come through just fine, verify and open.

This basically means that you cannot share your connection via Airport as it somehow disrupts and corrupts .dmg downloads on your own Mac.

Think Apple should have a look at this problem!!

Hope this helps some of you out!!

Great diagnosis and resolution! Why don't you head over to the Apple Discussions area (Apple.com > Support > Discussions) and post what you've uncovered? Worst case: Someone knows about it already. Best case: You're a heroine. :D

Thanks for posting your solution.

This has been bugging me since 10.4.10 -- although switching internet sharing over airport off makes the problem go away, it gives up a valuable service. I have also make it go away by switching the main internet connection from Ethernet 2 to Ethernet 1. Apple is working on the problem.

Internet sharing was obviously not the problem of the original poster, and it is not my problem, either. I have turned off all firewalls, internet sharing, and file sharing -- still my .dmg files come across corrupted. Here's some more clues to continue the investigation:

Even when I download them to a Windows computer on the network and then transfer the file over ethernet, nope, still corrupt.
And NOW, get this -- when I download it using a PC, put it on a USB flash drive, then transfer it to the Mac that way, still no dice. HOWEVER... it DOES open when I just try to mount it straight from the USB drive, instead of copying and THEN mounting!!! It must have something to do SPECIFICALLY with the writing-to-hard-drive process.

[Edit: Actually, there are multiple causes for the same result here, because Leela's solution obviously worked for her, and switching out the router has worked for the original poster.]

Wow - Expensive and time consuming fixes
 

I am having the same problem. I don't have the money to buy a new router and my PC works fine - so how is it the router? I am not sharing the mac connection with a PC via airport. The one about downloading to a USB device and then it failing when the file is copied to the HD sounds like a promising place to start for Apple. I searched their web site and didn't find this problem listed anywhere. How do we know when they have it fixed? Better yet, how do we download the fix?! I had this problem on OS 10.4. Upgraded to Leopard 10.5 from a CD purchased at Apple store and still have the problem. 1.83 GHz Intel Core Duo, 512 MB, Netgear router.

I am having the same issue as well
 

My ISP is providing us a wirless circuit and a T-1 that both terminate to the same router. The wireless circuit is the primary with the T-1 for failover. when we run on the T-1 I have no issues updating software and downloading .dmg files. When we are on the wireless circuit I do get corrupted .DMG files. My ISP has no macintosh experience so I am having to troubleshoot this issue without much assitance from them.

Does anyone know what is causing this?

After troubleshooting this problem for weeks it was determined that the ethernet plug on the Cisco router was the problem. My ISP came and swapped out the router and everything is fine now.

I had similar problems, after a couple of days of troubleshooting it turned out that the cause was the SPI Firewall on my router (Netgear 614). It seems it was rejecting various packets, and thus corrupting downloads.

So - check if your router has a SPI firewall, and if so, try turning it off before the download.

I was having the same codec overrun problems. I disabled the SPI Firewall on my Netgear router, and the code overrun problems on download went away.

- Don

This problem is making me crazyface.
 

Ok - I'm getting the "codec overrun" problem too - I only see the specific "codec overrun" message on the mac, although the PC is being funky too...

I've got 2 laptops: 1 macbook running OS 10.5.8 and one toshiba PC running vista (blech)

I've reproduced the 'codec overrun' problem while connected to my wireless router (turned off SPI, still an issue) AND while connected directly to the cable modem (scientific Atlanta DPC2100R2) provided by Comcast.

I don't have this problem when I connect to the network at my office across town (also comcast)

The PC is also able to download things just fine on other networks, but on my home network downloads get corrupted and madness ensues.

I'm fairly certain at this point that the problem lies with Comcast, or with my modem. BUT, contact with their support has been spotty - and they have insisted that my connection is just fine. Which it IS, aside from all the problems downloading things...

The problem isn't just with .dmg files either, I'm having various images online fail to load, streaming video won't load anywhere but youtube with any consistency, and I'm getting kinda frustrated...:confused: