When using a checkbox in IE, the checkbox isn't showing up - Is IE not supported? It shows up in Chrome.
Smartsheet is compatible with IE 11 and Edge.
If you're not seeing the checkbox in your browser, it's possible that you're on IE 10 or prior, or that you have an extension in IE that is preventing the checkboxes from appearing.
I'd recommend making sure you're on at least IE 11 and that you've disabled all of your extensions.
If the checkboxes don't appear after doing the above, contact support@smartsheet.com so our Support team can troubleshoot with you further.