Download corruption and CRC errors.
 

Hi guys, this thread has seen quite a few forums in the last two weeks as I attempt to diagnose a problem that's been plaguing me. I've been a Virgin Media customer for over 8 years (Since they were called NTL) and had no issues but all of a sudden last week all my downloaded files, Rar files and Executables so far both reporting corruption at a rate of around 70%.

For example I use a program called JDownloader to download things from Rapidshare, the program will report 'Connection Lost' and then occasionally 'CRC Error MD5'.

So at first I of course assumed this was an issue with the program, I reinstalled and updated etc, still there. Then I tried downloading some of the corrupt files straight through Firefox to take JDownloader out of the equation.

I still got corrupt files however and the problem was also now affecting Exe files, perfectly legit files that should have worked.

https://www.cableforum.co.uk/images/...2010/02/92.jpg

So at this point I turned to the hardware, maybe dodgy RAM or bad sectors on the HDD, I'd looked around on lots of forums and seen this suggested many times. I ran HDD checks and overnight RAM checks, all came back OK. So I used a laptop connected to the network to download the same links from. They all came back ok, but the second time I did it they too had corruption of ~50% of the files.

So it can't be the hardware. I format my computer, reinstalling Windows 7 on to a different harddrive.

Still nothing.

So it must be the network right? The router or the cable from the modem? That's what I thought, I replaced the router with a network switch just to see if that changed anything, the problem remained. So last ditch attempt. I plugged the modem directly in to the PC using a brand new cable (no small feat with it being around 20m long).

Still getting corruption errors.

It really can't be anything on my end, can it? A phone call to Virgin Media was very unhelpful with the usual 'turn it off and on again attitude' and the speed tests (Annoying as I never mentioned speed). I was told to turn off the firewall on my router, even though I told him I had replicated the problem without the router even being connected. Seems I have absolutely no hope of solving this from VM 'tech support.'They told me the line had only disconnected once in the last month and it was a stable connection. Could it be the modem then?

So here I am, a broken man. Does anyone out there have any idea what I can do to fix this?

Specs:
HDD 1 - Samsung SpinPoint F1 HD103UJ 1TB Hard Drive SATAII
HDD 2 - Western Digital WD5000AAKS 500GB SATAII
RAM - Corsair 4GB (4x1GB) DDR2 800MHz/PC2-6400 XMS2
GFX - Powercolor ATI Radeon HD5850 1024MB GDDR5
MOBO - Asus COMMANDO P965 Socket 775
CPU - Intel Core 2 Quad Q6600 B3 (2.4GHz 1066MHz) Socket 775 L2 @ 3.0ghz
PSU - Seasonic M12 700W Modular PSU
OS - Windows 7 Premium Home 64bit

Update:

The problem seems to start with connection freezing. The download speed and estimated time parts just stop (At this time all the lights on the modem also freeze) then it reports this 'Connection lost' thing. Seems to happen every few minutes.

https://www.cableforum.co.uk/images/...2010/02/93.jpg

Re: Download corruption and CRC errors.
 

Have you recently updated/changed your firewall/AV settigns/programs??

Re: Download corruption and CRC errors.
 

That's the thing mate, this happened and I did think about that, I've changed nothing at all. But since then I've changed everything and it's not fixed it.

If it was something on my computer then the error would not have been replicated on my laptop. I have tried resetting the router, returning to factory defaults, updating firmware. Formatting my PC. Had the connection plugged directly in to the PC ruling out a router problem. This is why I'm so stumped.

Re: Download corruption and CRC errors.
 

It could be hardware related (i.e..the connection) but more likely to be software... Do you have another PC you can test it on connected directly to the modem, this will confirm whether it's VM.. If not then add the router, then retest, then add your download manager and retest, then the firewall, then the AV...you get my drift ;)

It's exactly how you modular check suspected hardware faults/conflicts, you drop down to the very basic needed to work then you add the bits from there testing after each addition

Re: Download corruption and CRC errors.
 

The other possibilty is that the files are corrupt before you downloaded them.

Re: Download corruption and CRC errors.
 

I have a MacBook Pro which has Windows 7 running on it, I shall give that a run on OSX and download a lot of files see if there's any corruption with them, then we can rule out Windows if it still happens and focus on it if it does. Thanks!

Hom3R: Not at this rate, I've been downloading a lot from various places for years and never had a single CRC error, now in the past week I have it affecting 50% of all downloads. Nah definitely something wrong IMO.

To the tests!

Re: Download corruption and CRC errors.
 

I tried a downloading program called Orbit and like you I end up with a lot of files with CRC errors, (I also use VM) I have never tired Jdownloader and don't want to. I use a mini downloader which is part of IE7Pro, an add on for IE free (Google it) and although nothing as sophisticated as other downloader, it is fast and I have not had one file with CRC errors.

Re: Download corruption and CRC errors.
 

This thread isn't about illegal downloading but instead about CRC errors when downloading, if you can help please do so, if not then please don't go off-topic

Re: Download corruption and CRC errors.
 

Well it's not me who'll get in trouble if a content owner comes by and finds CF facilitating file sharing - Google the string TMHSAG. Hit 'I feel lucky' if you want, it's that easy.

Re: Download corruption and CRC errors.
 

Yes I know exactly what TMHSAG is, but this thread is not about that, you have no proof as to if the picture he posted is even off his PC..

:rolleyes:

Now back on topic please

Re: Download corruption and CRC errors.
 

That was a test since it's got lots of links meaning it's a good way to test the problem. It's hard to replicate it without a list of links. What I normally download is not the point either, you don't know me.

Ok, removed it, sorry for any trouble caused, but please try and help rather than flame.

Re: Download corruption and CRC errors.
 

Excellent - I have removed my post and am seeking Hormone Replacement Therapy :D

Now then.

You use a router? Any software firewall, Zone Alarm, etc?

Usually CRCs are sourced from things like application layer firewalls on routers or on your PC helpfully trying to screen traffic to make sure it's ok and in between breaking it.

Try booting in safe mode with networking from behind the router. We know it isn't the router as you've already tried directly connected with no change.

To eliminate network corruption pop open a command prompt and do this:

ping -t -l 1460 www.virginmedia.co.uk

Leave it running for ages, and when you get bored hit CTRL-C and see if any errored.

You can also do the Mac equivalent if you wish too.

ping -fs 1460 www.virginmedia.co.uk

Don't leave the Mac one going for too long as it is a flood ping and looks like a denial of service :D

Re: Download corruption and CRC errors.
 

I use jDownloader to download from Rapidshare every day without any issues - have you tried changing which RS servers you use by default in your RS account ?

Re: Download corruption and CRC errors.
 

Thanks tried that matey.

https://www.cableforum.co.uk/images/...2010/02/90.jpg

Thar she blows. What next? :S

Re: Download corruption and CRC errors.
 

Not network related in that case - you'd have seen some errors if that were the case.

Next on the list would appear to be a nice long download from somewhere else such as the VM FTP site.

I despise Rapidshare in any and all guises so am quite happy if VM are messing with traffic to and from there but they aren't in this case.

Re: Download corruption and CRC errors.
 

I'd have thought that would be what was causing the 'connection lost' and the subsequent 'CRC errors' though?

Will have a look at the VM FTP, think downloading a large file from them would be a good idea, do you have the address please??

Re: Download corruption and CRC errors.
 

Had CRC errors when i built my comp and it was down to bad computer memory Changed memory had no CRC errors.But that was my case

Re: Download corruption and CRC errors.
 

Yeah, tried different memory though (on my laptop), so yeah no my issue I'm afraid :(

Re: Download corruption and CRC errors.
 

i had this problem on an old Netgear router and disabled SPI and sorted it.

Re: Download corruption and CRC errors.
 

Screw it, I'm going to upgrade to 50mb, new modem, new router, line checks from a technician and apparently will cost me £13 less a month. (For a one off fee of course).

Should fix the issue.

Re: Download corruption and CRC errors.
 

Have you tried removing the SPI in the routers settings as advised above? I have had a similar issue and it fixed my problem with corrupted iTunes downloads.

Log in to router > Go to WAN settings > untick SPI > save settings

worth a try ;)

Re: Download corruption and CRC errors.
 

Well the thing is I have the problem with no router at all, so it's not a router issue. I shall let you all know what happens when I'm upgraded, will order tomorrow. Thanks for trying all.

Re: Download corruption and CRC errors.
 

ah... I see. Let us know how you get on :)

Re: Download corruption and CRC errors.
 

Bilko I had the same problem with rapidshare. It was working fine for years until my connection went down one day and it’s never been the same since. Even updates from Microsoft would fail and be corrupt when trying to install.
Since then I have had to transfer over to using newsgroups. The particular provider I use has a European server and that seems to have sorted the problem. I still have trouble downloading directly from the web IE Upgrades/drivers but at least I can download my other stuff now :/

Re: Download corruption and CRC errors.
 

Hey you live near me, I'm in Droylsden not far from Ashton.

But anyway, I can't think why this just started happening, the only thing I can point to is the modem or Virgin Media. But it's not a widespread problem so most likely is my modem. I'm getting it all replaced on the 26th, will be sure to let y'all know how it works out incase anyone else has this issue.

Re: Download corruption and CRC errors.
 

Eeek, used to do a lot of canoing and sailing at Debdale park :p:

Re: Download corruption and CRC errors.
 

Ha, small world :D

Re: Download corruption and CRC errors.
 

Re: Download corruption and CRC errors.
 

Cheers man. When I phoned virgin they were just worried about the speed too. Not noticed any problem with the speeds really. I'm always downloading at 2.3mb/s with jdownloader where the problems happen all the time.

Ah well. Even if they continue on the faster line at least I can download corrupted parts quicker. If it does continue I'll probably switch isp's.

Re: Download corruption and CRC errors.
 

I had this problem a few days ago and just changed rapidshare servers and it works fine now. Maybe try that?

I pay for newsgroups but meah still easier to find what you want on rapidshare

Re: Download corruption and CRC errors.
 

I was getting sick of re downloading files using my rapidshare usuage up. Newsgroups is only £7 per month for Unlimited downloads not like RS 5gb per day. Hiroki if you find yourself a good forum which links stuff its just like using rapidshare but better IMO

Re: Download corruption and CRC errors.
 

Any recommendations of forums? I've had a lot of help off the people on this site but I have yet to find a decent place that has what I need so I have had to resort to using both torrents and rapidshare again

Re: Download corruption and CRC errors.
 

PM sent Hiroki

Re: Download corruption and CRC errors.
 

ever thought it could be the downloader ur using and not the connection?

Re: Download corruption and CRC errors.
 

Yeah been through all this, it's not the program and it's not rapidshare because corruption occurs downloading from official sites with Firefox.

Re: Download corruption and CRC errors.
 

Sorry if I'm being ignorrant, but isn't upgrading going to just get the corruption quick?

Re: Download corruption and CRC errors.
 

Well there's a chance of that, or there's a chance it's my modem in which case the upgrade provides me with a new one and also the chance a technician will be here so I can show him the problem.

The faster connection is actually going to cost me considerably less per month, so it's a good thing to do I think.

Re: Download corruption and CRC errors.
 

I had a problem where any exe, zip, PPT would fail but "data" files such as MP3s would download. Applications would complain about lack of publisher... solved with a tweak of the Jumbo Packet setting in the server I use to connect to the Intenet. Set it back, problem returns, get it bigger, all is good. The problem came from nowhere as the system had been just fine...All attached devices had the same issue.

(Windows Server 2008 R2 connected to VM via a couple of AV Homeplugs. Windows 7 Enterprise running on 2 netbooks, 1 Compaq, 1 Tosh, 1 Mesh...)

Re: Download corruption and CRC errors.
 

It might be worthwhile asking on the Virgin Media newsgroup to see if they can check the UBR/cable that you are connecting through. High levels of error correction might result in corruption of downloads*, as could high CPU-utilisation or something else that is causing random packets to corrupt, which would be enough to throw off files that don't in and of themselves have error correction or are tightly compressed.

There are two reasons that phone support will be looking at speeds, and while you can probably figure the first one out yourself the second is that most of the things that would cause errors in downloads would (or at least could) cause slow speeds on your connection: packet loss; utilisation; throughput delays.

* In that while the equipment does forward error correction extremely short bursts of extremely high errors could be enough to cause the packet to be "corrected" wrong. Sudden burst noise that is short lived, spikes in data like a DDOS attack, or even some underlying condition like Additive White Gaussian Noise could be enough to distort borderline bits of signal up and throw off some packets. Effectively the density of the data that you're downloading makes it more susceptible to these issues - on images because of the nature of the encoding a duff bit or two will give you a bleary pixel or some sort of quasi-steganographic distortion. With something that requires unpacking, a handful of duff bytes could throw the whole thing off.

Re: Download corruption and CRC errors.
 

If you want to post a link to a file that you consistently can't download properly, I will try it and report back. Please just make sure it's a "legal" download of some sort...

Re: Download corruption and CRC errors.
 

@Graf von anonym: Hmm sounds interesting but unfortunately I don't know much about new groups, how would I get to that and post on there? Thanks.

@smokieUK: Well I have tried it with many many different files, sometimes they work and sometimes they don't. if it was just one file i'd assume that file was corrupt. But all the files i've had corruption problems with have eventually been downloaded without them, so it's not the file.

Re: Download corruption and CRC errors.
 

Virginmedia have a support newsgroup that gives you "direct" access to the 2nd line team. I think that there's a guide in a sticky at the top of one of the forums for it, if not it's a relatively straightforward process; do you have Outlook Express on your computer?

Re: Download corruption and CRC errors.
 

No I don't, don't really like it, is there another way, perhaps through google??

Re: Download corruption and CRC errors.
 

So I got 50mb installed about 10 mins ago, unfortunately the CRC errors are still there. Such a strange problem.

Will install Outlook Express and ask the 2nd line peeps what it could be. So annoying.

Re: Download corruption and CRC errors.
 

If you have reported the facts correctly it HAS to be something after your modem and before the "serving server". So as someone says above, get VM to check the box etc in your road.

Re: Download corruption and CRC errors.
 

Yeah exactly, I really have replaced absolutely everything on my end and now that includes the modem. How exactly would I go about getting them to check this though? Last time I called 'tech support' they just got me to run a speed test on my line and told me everything was fine. :(

Also of note is the fact a friend of mine also experiences the exact same thing but lives on a different road (with a different box no doubt).