What happened on August 16
(Posted at 5:35 AM GMT, updated first two paragraphs at 11:45 AM GMT)
On Thursday, 16th August 2007, the Skype peer-to-peer network became unstable and suffered a critical disruption. The disruption was triggered by a massive restart of our users' computers across the globe within a very short timeframe as they re-booted after receiving a routine set of patches through Windows Update.
The high number of restarts affected Skype’s network resources. This caused a flood of log-in requests, which, combined with the lack of peer-to-peer network resources, prompted a chain reaction that had a critical impact.
Normally Skype’s peer-to-peer network has an inbuilt ability to self-heal, however, this event revealed a previously unseen software bug within the network resource allocation algorithm which prevented the self-healing function from working quickly. Regrettably, as a result of this disruption, Skype was unavailable to the majority of its users for approximately two days.
The issue has now been identified explicitly within Skype. We can confirm categorically that no malicious activities were attributed or that our users’ security was not, at any point, at risk.
This disruption was unprecedented in terms of its impact and scope. We would like to point out that very few technologies or communications networks today are guaranteed to operate without interruptions.
We are very proud that over the four years of its operation, Skype has provided a technically resilient communications tool to millions of people worldwide. Skype has now identified and already introduced a number of improvements to its software to ensure that our users will not be similarly affected in the unlikely possibility of this combination of events recurring.
The Skype community of users has been incredibly supportive and we are very grateful for all their good wishes.
florian_matusek commented Monday, Aug 20
Thanks for the info.
So was this routine update this Windows update that we got on this day? Or some other Skype "update"?
xilakju commented Monday, Aug 20
To be honest, this sounds like a PR fairy-tale to me. 
Anyway, let there be another four (or even more) years with no downtime! Yippi-kee-yay!
acceinlondon commented Monday, Aug 20
Thanks for the explanation. I can live with short blackouts every 4 years or so too.
mike259768 commented Monday, Aug 20
Must have been a nightmare for Technical Support. It's good to see a clear cause and corrective measures. There is a broader issue for all on-line services that I have covered at http://justenoughtechnology.typepad.com
bobblock commented Monday, Aug 20
To the 'Skype People' - good job getting things back up and running. You have provided an excellent service and you should be applauded for that. These types of unexpected things happen and it is obviously near impossible to plan for contingencies. I hope that all skype users appreciate the high level of 'free service' you have provided to us all and are understanding. Keep up the good work!
arcoiris_azul commented Monday, Aug 20
And by the way... What about the SkypeCast System ?¿ The SkypeCast utility is a disaster since 16 of June. The famous error 5, the sounds artifacts and the super-Big sound problems in the last days, the impossible way to join a Cast ... etc etc ...
Now, we all know that the skype team can resolve the big problems when they really whant to. Please do something nice with the SkypeCast utility. Thanks.
yaser_xp commented Monday, Aug 20
So that was the reason.
I guess that I'll have to disable the update service from now on 
A really BIG "Thanks" for all your efforts!
jamesnjacqui commented Monday, Aug 20
Thanks for the update. Surely this shows a distinct lack of change control and release management. Who on earth updates every server globally at the same time, especially when you know there is to be a reboot? May I recommend a splash screen notification in 4 years time, so that we don't spend hours trying to self fix?
hve.dk commented Monday, Aug 20
If the problem was caused by an old bug - How are you able to prevent this from happening again without letting all Skype users upgrade to a new (fixed) version of Skype?
zquack commented Monday, Aug 20
How will this be prevented in the future, with the next Patch Tuesday scheduled to be September 11?
burner- commented Monday, Aug 20
"We can confirm categorically that no malicious activities were attributed or that our users’ security was not, at any point, at risk." Thast not full truth. Yes no security leak risk. But after skype login start work there was one old problem. I have reported of that old bug but seems that its not fixed. There is no limit to how many peers skype server deliver relay node info. So when skype start working NAT users start using limited amount of relaynodes to theirs calls. Skype peers DDOS working relaynodes down. I have 20/20Mbps connection on home and over 2700 simultaneous skype connections was too mutch to firewall and connection. I get network problem reports from many our customers. over 50 people company networks go down. And why? Because that old bug is not fixed. I make first report of that over two years a go.
acceinlondon commented Monday, Aug 20
those sneaky guys at Windows Live Messenger. It's all their fault.
fabrimarvel commented Monday, Aug 20
Thesaurus: Verb 1. suffocate - deprive of oxygen and prevent from breathing
- nuff said!
sr.wombat commented Monday, Aug 20
I may be missing something, but if it was updates to Windows which caused the disruption, why was I, a Linux user, booted? I wasn't trying to log in at the time. My server, and Skype had been running for several days.
williamlouth commented Monday, Aug 20
Hi,
I was wondering whether you could probably give us a timeline leading up to the resolution that points out the techniques and processes used in performing the root cause analysis. I would be very interested in hearing how you were able to go from a system wide failure down to a line and code and were the time lags in the data collection and analysis occurred. I not looking to know the actual tools but more so the type of tools: system monitors, event logs, diagnostics images, trace files,.....
regards,
William
martin.porcheron commented Monday, Aug 20
Please guys, I use Skypeout, I want to rely on it but I can't. If you'd have given more information during this time prehaps I would still be with you, but alas my trust of you is broken.
ruimafm commented Monday, Aug 20
Bem... Então a culpa é da Micro$oft
O que interessa é que está a funcionar.
Rui
hablalatino commented Monday, Aug 20
I was surprised to discover how dependent of skype I am. I went and download the microsoft messenger (which I used to used before)and it really sucks!
Well I really hope that we don't have more problems in the future and that greedy Ebay people don't use this to charge us money.
tijlvanpraet commented Monday, Aug 20
Now how about some compensation?
Fact is a lot of us are paying for services that we couldn't access for over a day. The least you could do is offer some sort of compensation. Give us paying customers some free SkypeOut credit, extend our SkypIn / voicemail / Skype pro subscriptions... Do something!
szitac commented Tuesday, Aug 21
It all comes down to.. Skype is very user-dependant. I guess p2p works that way, and while more users are online, more robust is the network, maybe centralized redundant servers are better than a p2p solution..
Anyways, keep up the good work fellas!
nicolas.sanguinetti commented Tuesday, Aug 21
"We can confirm categorically that no malicious activities..."
Oh, come on, that many people still using Windows is not considered a malicious activity towards humanity?
rocco.sicilia commented Tuesday, Aug 21
"Oh, come on, that many people still using Windows is not considered a malicious activity towards humanity?"
Yes, of course...
spineros527 commented Tuesday, Aug 21
Thank you to all the people who run Skype. You kept me in contact with my loved ones on the worst days of my life, therefore you were my lifeline, literally.
Things do happen from time to time. Your reaction and effort to fix what was wrong deserves a big cheer. Thank you Skype from the bottom of my heart.
actagamut commented Friday, Aug 24
I just want to say to all those who feel they got the major shaft for the downtime...Why is it that when people get things for next to nothing they want to bite the hand that feeds and intentionally go off the deep end? Things happen, the world isn't perfect. There are still email servers, chat messengers, etc. Take a vaca and prioritize; use the money being saved to help humanity instead of bitching about it. Oh, and as far as compensation?? Pay phones now charge $00.50...do the math. If Skype deliberately sent a malicious code that melted one's computer, giving one 3rd degree burns while causing one to go deaf from an unadulterated screeching sound...well then I suppose compensation would be in order. Then again, that person wouldn't really need to use the phone ever again, eh?
engelbdo commented Monday, Aug 27
I haven't seen such dedication and passion in a very long time! I 
Skype! Its a great tool i use daily for personal and business purposes -I can say its almost part of my daily lifestyle! It was the most isolated two days i had in a very long time! ... but I survived! Thank you again guys!! You guys 
jim.shaver commented Tuesday, Sep 4
Maybe if the linux version wasn't a piece of ****(more linux users would use it) and you would have less of a reliance on windows computers carrying all the load in the distributed network
fragrantwishesatday commented Saturday, Oct 13
Hello there...
does anyone have any insite as to why i cant open other pages on my pc when using skype ?
I have a Sony Viao laptop "a new 40 gig hd , 1 gig of new ram ,p4 processer " and reformatted with "XP home" , and high speed dsl.
as soon as I start talking on skype , my processer overloads to 100% , but... thing is , if I'm not using voice on it ,running programs or watching a dvd , it does fine , no problems then...
please .. pleaseeeeeeeee email me ( prinz_of_pazzion@yahoo.com )
thank youuuuuuuu 