The requirement I'm working on requires to read a CSV file with temperature measurements. But Fahrenheit or Celcius symbols are causing exceptions when converting csv blob file to string using toString(). I ran into this issue many time in the past but it's because of mysterious special characters that get inserted because of copy-paste. This time i inserted these symbols from excel insert tool box, it didn't work. I queried some data points with these symbols in my salesforce org and pasted in csv. It didn't work either. Please let me know your thoughts. Thanks.

  • Have you tried EcnodingUtil.base64Encode (documentation)?
    – Adrian Larson
    Dec 23, 2015 at 18:41
  • 1
    once you save your CSV file on your local machine, open it in a text editor that can display hex and verify that the degree sign you are using is a valid UTF-8 character. The degree symbol should be UTF-8 00B0 = ASCII B0. MSFT Excel won't save CSV as UTF-8 but this typically is a problem only with asian languages or eastern european character sets when it comes to SFDC
    – cropredy
    Dec 23, 2015 at 18:45
  • @AdrianLarson Yes. I tried that. It didn't help. Still getting the same error.
    – Avinash
    Dec 23, 2015 at 18:54
  • @crop1645 I have opened the csv in notepad++ and encoded the whole text to UTF-8 and it works. The funny thing is I encoded it to UTF-8 many times this morning, but forgot save it and thought it is not making any difference. As you mentioned text editor, I thought of giving it another try and it works. Thanks.
    – Avinash
    Dec 23, 2015 at 19:04
  • this has made me more curious - how ae the CSV fles coming into apex? Via VF upload, REST/SOAP API, inbound email handler?
    – cropredy
    Dec 24, 2015 at 0:12

1 Answer 1


Somehow, your users are inserting into their source spreadsheet a character that the spreadsheet can't encode as a valid UTF-8 character upon SAVE. SFDC only accepts UTF-8 characters. ASCII 00-FF maps to UTF-8 asis and the degree symbol ° is ASCII B0. So you would expect to be fine.

But, if the user is copy-pasting the combined degree+C symbol (UTF-8 = U+2103) into Excel and then saving as CSV, that is not in ASCII 00-FF and won't save as UTF-8 by Excel. Same issue with which is UTF-8 U+2109

Who knew there were such UTF-8 characters? Cool.

MSFT Excel (through 2013, last version I have checked) will not save CSV files as UTF-8. Stackexchange discussion on VF uploads of CSV files here.

Example: does not save as e2 84 89 but instead saves as 3f = ?

Open Office does have a save as CSV with UTF-8 encoding but your org may not use Open Office.

Google Docs does have a save as CSV with UTF-8 encoding but your org may not use Google Docs and anyway, as a cloud solution, having to save the file in Google Docs to your desktop and then upload to SFDC is a user bummer.

  • Re encoding the file in notepad++ has a side effect. Even though we are looking at a csv, when we re encode, it is actually changing the format to unicode text. When I duplicate the csv, both the original and copy are changed to unicode text. I even pasted UTF-8 encoded text in the individual cells, but still getting the blob error. I don't understand why it would throw blob exception when the text was encoded into UTF-8 and pasted into the cells. Will the text loose its properties when I paste it in csv? How can I import ℉ now?
    – Avinash
    Dec 28, 2015 at 21:22
  • If using MSFT Excel, "save as CSV" will never save chars pasted in as UTF-8 as UTF-8.
    – cropredy
    Dec 28, 2015 at 21:49
  • I'm not saving xlsx file as csv. I open a csv and paste the UTF-8 encoded text into the cells. Even that is not working..
    – Avinash
    Dec 28, 2015 at 22:01
  • as I said, MSFT Excel will never, ever save UTF-8 encoded chars in a .csv extension
    – cropredy
    Dec 28, 2015 at 22:02

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