Just a quick post to share a tip I discovered this morning. I was generating a CSV file and for some reason when I went to open it in Excel, I got a message saying the file’s extension was CSV, but the file format was SYLK. Clicking through a couple message boxes opened the file up just fine anyway.
A bit of digging turned up the Wikipedia page linked above, and within it the format syntax description:
”’ID”’ record:
Use:
A header to identify spreadsheet type and creator.
Must be first record in the file.
Yep. If the first record of your CSV file is “ID”, Excel will attempt to intepret the file as SYLK. Changing “ID” to anything else (including “Id” or “id”) fixes the issue.
Adam Lear 
WarrenP
/ April 25, 2011That’s hilarious. Too bad you can’t just go on the Excel project’s sourceforge page and post a bug. 🙂
Warren
Doug Carr
/ December 5, 2011That is just crazy. Thanks again Microsoft for thinking that your software is smarter than it really is.
I just ran into this issue and your tip solved the issue right away.
I thank you so very much for posting this.
Doug
Anna Lear
/ December 5, 2011You’re welcome. Glad I could help! 🙂
thebitguru
/ March 21, 2012That dialog was annoying, thanks for posting the solution and the reasoning behind it!
jessamin
/ May 24, 2012I love that I just entered “why excel thinks csv” into google and it autocompleted with sylk. Thank you for posting this solution!
Neil Weinstock (@NeilWeinstock)
/ May 31, 2012Most helpful, thanks for posting. I was flummoxed by this until I searched and found this post.
Gary Hughes
/ September 10, 2012Just arrived here through a Google search. Thanks a lot for your post, it’s solved my problem.
Crazy behaviour in Excel though. Surely checking for a .slk extension would be enough rather than assuming that your .csv must just be wrong? Even just opening as a CSV if the first column name is ‘ID’, the extension is .csv and the SYLK check failed would be better.
Paul S (@Knowsitall69)
/ December 20, 2012Anna – Thank you for saving me a lot of time!
Brian B
/ December 3, 2013Just wanted to add my thanks to the others above. I had the same experience as jessamin — I Googled “excel thinks csv is”, it filled in SYLK and up popped your post and the solution! Perfect…. THANKS!
Eric
/ January 22, 2014You saved my day – thank you!
Greetings, Eric
PS: Found you by searching “excel csv sylk” at google (position: 3)
Alex B
/ May 9, 2014Thanks so much. A bit more detail: Excel will mess this up not only if the field name is ‘ID’, but also if the field name ends with ID, such as ‘messageID’.
Jaume Albaigès
/ June 27, 2014Thank you for the tip!
Chris Riesbeck
/ July 7, 2014Add me to the list of “huh?!” and “thanks!”
Pierre M.
/ September 4, 2014Thanks a lot Anna! You saved my day (s)!
Just to add:when you try to open a CSV file you just saved from Excel itself, it fails! How could a software do such stupid things ?
Sven Berkvens-Matthijsse
/ September 25, 2014Thanks very much, just ran into this and your explanation saved me a whole lot of time 🙂
Dave Patterson
/ January 19, 2015Thanks for posting this. So glad it turned up first in my search for how to solve this annoying problem.
Ki Hulme
/ January 30, 2015Many thanks for the post. And thanks Microsoft for more none-sense.
Bastien
/ February 13, 2015Many thanks for these explanations on another great functionality of a Microsoft software.
marcus
/ May 13, 2015Fab tip, thanks for that!
davidcawthray
/ June 1, 2015This posting saved a significant amount of head scratching!! Thanks.
fogbear
/ July 22, 2015Wow! More than five years later, and this post is still generating responses. It’s one of those eternal Microsoft annoyances that I just ignored for years until I finally decided to try to find an answer.
elecorn
/ August 3, 2015Thanks so much! I was wondering about that.
praflo
/ August 16, 2015Thank you Anna. This saved me some time.
Taibe
/ September 20, 2015Thank you so much. I don’t know how I’d ever have figured out what was wrong without your post.
jrw
/ September 25, 2015Still a bug in Excel 2013
guntherinasia
/ October 20, 2015Eternal gratitude for this post.
Roger Fitch
/ November 27, 2015Great thanks,sorted 🙂
Ricard
/ November 29, 2015Very Useful. Adding to Alex B comment, in my case Excel was also confused by a first field called IDPatient.
Eric James Stone
/ January 18, 2016Thanks for posting this solution. I was mystified as to what I was doing wrong with my CSV format.
Brian
/ January 19, 2016Confirmed still a bug in Excel 2016
Noud van Klinken
/ February 10, 2016Thanks Anne!
Piskvor
/ March 8, 2016Wonderful. Thanks!
If you absolutely *need* to have “ID” in the first column, consider ” ID”, or worse, =”ID”
The latter one is technically Excel syntax, not CSV, but Excel will parse it as its string anyway. Weird stuff.
Adrian
/ March 8, 2016Thank you! Saved my evening if not more.
Kroh
/ March 8, 2016Wow, can’t thank you enough for posting this solution! Couldn’t figure out why csv files as output were fine sometimes and were interpreted as SYLK files in other cases. You saved me HOURS of head banging!
Frank SanPietro
/ March 24, 2016Many Thanks. Found you via Google search and the tip prevented me from redoing a bunch of work. Echo the frustration of others re: why MS has to “overthink” things sometimes. Thanks again.
Ghislain
/ August 9, 2016Wow….
You make my day !!!
Stevens BIDEAU
/ August 26, 2016the explanation:
https://support.microsoft.com/fr-fr/kb/323626
steinar
/ September 9, 20162016 – thank you!!
WHY!
David D. LaCroix
/ September 9, 2016So I’m not the only person encountering this problem today. Hilarious.
hoshantm
/ October 10, 2016Thanks! You helped me resolved this problem in a minimal amount of time.
Malcolm Farrelle
/ November 25, 2016Like others – thanks so much. Now if you could tell me why my C200 Doesn’t start 1 time in 12 I’d be super-impressed!
Liam S Kelly
/ November 28, 2016Thanks Anna,
This has been annoying me for over a week. Applied you fix – sorted in seconds. Still a bug in Excel 2016
JB
/ December 7, 2016Cool thanks for the post!!
Darryl_G
/ January 10, 2017Awesome! Thanks Anna for helping us quickly solve this mystery! 🙂
Thanks Microsoft for keeping things interesting! 😐
Asko
/ January 25, 2017THANKS!
gReG
/ February 22, 2017Just to let you know I am yet another person helped by your post. Thanks for taking the time to post it. The gift that keeps on giving…. 🙂
Ingo
/ March 22, 2017Thanks for your post, still valid after seven years! Ran into the problem, googled SYLK and found a lot of pages advertising intimate moisturiser. 😀 Adding “Excel” to the search terms brought me here to enlightenment.
Holden Hackbarth
/ May 5, 2017An amazing coincidence, just ran into this problem myself. Thanks for your post, fixed the issue…
Dan
/ June 27, 2017Thanks. You are a lifesaver.
Ali Baig
/ July 13, 2017Saved my day
Dawn
/ July 20, 2017Great tip I ran into this issue and was able to fix it quickly. Thanks.
robertcday
/ July 21, 2017Nice fix – helped me at work. Thanks, boss. 🙂
Robert.
FlailingElbows
/ July 28, 2017Aaaand, another person here who just found the same issue. So, yeah, 7 years and still going strong. Thanks for the post!
Dirk-Pieter Tas
/ July 31, 2017Thanks for your post, fixed the issue after many frustrating months.. 🙂
S
/ August 3, 2017Thanks for your post, like you I just clicked thru several times and it opened fine, just figured it was one of those quirky microsoft headaches. Thanks again.
Jeff Sararas
/ August 14, 2017Yeah, here too. Amazing- seven years later and MS still hasn’t fixed a simple bug. Too bad you don’t have a donate button! You could be making some $ off of Microsoft’s continuing ineptitude. 🙂
sukh
/ August 17, 2017Awesome tips. Thanks a lot.
Martin Lagerholm
/ August 28, 2017Great thanks for the help – saved me some time
Phil Petts
/ September 23, 2017Thanks – this post definitely saved me some head-scratching!
James
/ September 26, 2017We have discovered if CSV is changed to UTF-8, the SYLK problem disapears (without change ID to Id)
Gresley Wakelin-King
/ October 25, 2017thanks for your post! – and more on this story, if you use your not-SYLK-not-CSV file to create points for your GIS, your site locations will be amusingly scattered across the landscape, to the detriment of your science.
M
/ November 16, 2017Even other ‘ID’ words trigger the error: IDENTIFIER, IDEALISTIC, IDiocy…
VENKATA CHILUKURI
/ November 27, 2017I encountered the same problem today. I was thinking I was doing something wrong. Then I googled and found this post. Thank you!
Curt's Mom
/ December 13, 2017Thanks for the info…stupid excel…LOL
Lisa Bos (@lisabos)
/ December 20, 2017Another thank you.
leonofdesert
/ June 18, 2018Well, we are at 2018 and I’m here to complement that he will tell it when your first data contains ID. e.g:
ID_MY
myID
ID
DavID
IDontcare.
Tom W
/ June 27, 2018now is 2018, still there … Thanks LOL
Minh V
/ July 27, 2018Thanks for this. It helped me at work 😉
jeanluchayes
/ July 30, 2018Amazing. Thank You.
ST
/ August 29, 2018Just wanted you to know this old post just probably saved me hours of anger and frustration. THANK YOU!
ST
/ August 29, 2018Just wanted you to know that this little post is still helping people (me!) years later. THANK YOU!
Aaron V
/ December 11, 2018Haha! Thanks for saving me! This is still helping 8.5 years after the fact 🙂
Paul Marti
/ December 30, 2018Ending 2018 and your post saved me, thanks!