Frequent "corrupt" download files

As a new mac user, I have little experience but heard all good things about mac. (but very good at pc)

I however encountered this same issue as most of the downloaded dmg files are "corrupted" in my first two days. Read a few posts here and in other forums, here is what i did:

1. Tried to use "disk utility" to find error and repair the partition and disk. As folks are saying most likely it can be a bad disk or bad memory, i.e: hardware problem. I was thinking i just got bad luck as it is a brand new mac air.

Well, it did find one error on disk: a group value is wrong, should be 0 but is now 80. fixed it.. Tried to download the same dmg files(office for mac trial, and os upgrade). still corrupted.

2. Saw someone mention that could be wireless router problem. As I have PCs and Ipad and other devices running on the same router and internet, I do not think that is the case. But i did(now as i look back) encountered a few werid error when i used my pc to download some microsoft updates too. And I may have blaimed win8 wrongly for its suck app store(*_^).

3. Called apple support, the junior guy can not fix it then passed me to the senior guy.Here is how we fixed it (but I strongly feel also because I reset my cable modem as well during the fix):

Reboot the mac, get into the restore mode, from there use the disk utility app to find and repair the error i mentioned above in 1.

Reboot, although I can not see any updates of the OS in the apple store no more, i can still go to the website get the dmg downloaded and now, bingo... it works...

And again, now putting all these together, I think i may also hooked up with a bad modem on the time warner cable side for a few days ut as i most tiem do not download any new software, i never paid attention to it... this may explained why we can not get youtube play videos smoothly....

and anyway, except now the new os drain my battery like crazy..(i only get 3.5hours out of the 7hours claimed), this machine works like a chime....i really like the smart mouse pad.... love it.

Oki, hope this may be helpful for someone...

And apple, please fix the os and show me the 7 hours battery....

I have another interesting data point in this topic. I've started experiencing these checksum errors since last week, when I switched internet provider (now UPC 60Mbit cable with a Cisco EPC3925, was a 10Mbit ADSL connection).

I never had the problem before.

Moreover, if I download a file with scp (ssh-based secure network copy) I never get a complete download, it always complains long before the end about "corrupt packet". So the good news is that scp catches the error before it has downloaded the whole file with the error half way:-)

I have just now disabled pretty much all security measures in the cable router (SPI firewall protection, which protects against DDOS attacks, IPv6 firewall protection, ping/port scan protection) and the first download I tried succeeded.

I'll leave this situation as-is for a while, and report back here if it turns out I'm still getting corrupted downloads and I was just lucky tonight.

Upgraded to new Cisco cablemodem/router combo (forget the model number, but it was the latest docsis standard, was 32mbps down/7 up) and although it was blazing fast, I was getting corrupt updates to Lightroom. Spent weeks with support on both ends, and neither one figured it out. I ran across an article about Cisco's stuff corrupting downloads and found that all the very large downloaded updates before the change in the device worked no problem.

Returned the device, put my old cablemodem back and added a new wireless router and everything works fine, albeit slower. Sadly I sold the perfectly fine wireless router on ebay, thinking this device was much better.

What really ***** big ones is that the Cox cable people threw up their hands when they were told it was the cisco combo they sold me; they said for another $120 a year I could get "home network support". So the lesson is: no combo boxes; get the one device they claim to support (idiots) and then hang whatever you want from there. They cannot wiggle out of their responsibiliity that way.

This is all good, but I'm going to add just one thing that you missed as a possible cause of download corruption: a bad Ethernet cable. I've been trying for three months to figure out why my Mac Mini had sporadic problems with corrupted downloads, while my MacBook Pro connected to the same network did not. I wasn't in a giant hurry to fix the problem as I had the "sneakernet" workaround (downloading updates to a portable drive on my MacBook and walking the drive over to the Mac Mini to install). But it's been an annoyance, so after getting a "honey do" request to update software that kept saying the downloads were corrupted, I got to researching and stumbled across this post suggesting that the problem had something to do with the router.

Before I got to calling my ISP, it occurred to me that the MacBook Pro was connected via wireless, but the Mini was directly connected to the Ethernet. So I disconnected the Ethernet cable, turned on the wireless, and re-initiated the download. Voila! Perfect download. I replaced the Ethernet cable with a different one, turned off the wireless and tried again and...yes, voila! Perfect download.

I imagine there might be problems out there with routers, but before you drive yourself and your ISP nutty, you might want to check your Ethernet cable. Could it be that those who have had trouble with upgrades to faster/better routers could also be suffering from bad cable syndrome? Maybe those old Ethernet cables that worked fine at slower speeds have flaws in them that show up when you try to push more data thru them. My guess is that the problem is the connector itself rather than the cable, but who knows?

Cindy

Hi all

I Have recently had a frustrating couple of days also,same problem initiative attempting to download an update on a new Mbpro 13 inch

ccorrupt files messages and such . Then realised similar problem with OS X update. Smaller files no problem. Another Mbro similar problem.

short version of solution

as i did not have an adapter for new retina Mbpro, I disconnected wireless on older Mbro, connected to modem with Ethernet cable.

downloaded files

saved to thumb drive

thumb drive to new Mac

copy to application

install

all ok

so it appears to be the wireless side of things

so further I will look at

Reboot the modem router. ( as I have not done that)

Update of router ?.

Look into connect airport to modem ?

all best