TI-84 Error Fixes & Troubleshooting

Your TI-84 Plus CE runs a calculation but nothing appears on the graph screen? This guide covers all 7 reasons why the graph may be missing and exactly how to fix each one.

Calculator shows "Validating OS" and won't boot? This is a known firmware loop. Follow these exact steps to break out of the loop without losing your programs.

TI Connect CE says "No calculator detected" even though it's plugged in? Here are the 5 most common causes and how to fix them on Windows and Mac.

Getting a long decimal when you expect a fraction? Learn 3 ways to display exact fractions on the TI-84 Plus CE — including the MATH→Frac shortcut and changing default settings.

What does ERR:SYNTAX mean? What about ERR:WINDOW RANGE or ERR:DOMAIN? This guide explains every common TI-84 error message and how to clear it.

ERR:SYNTAX is the most common TI-84 error. It means the calculator can't parse your expression. Here is how to find the exact typo with GOTO and the 6 mistakes that cause it.

ERR:INVALID DIM usually means a stat plot is turned on while its lists are empty. Turn plots off with 2nd Y= → PlotsOff and the error disappears. Full walkthrough inside.

ERR:DIM MISMATCH means two lists or matrices have different sizes — most often L1 and L2 in a stat plot. Here is how to check list lengths and fix the mismatch.

ERR:DOMAIN means you passed a value the function cannot accept — like sin⁻¹(2) or a probability above 1 in normalcdf. Here are the common causes on AP Statistics problems.

ERR:DATA TYPE appears when a command receives the wrong kind of value — text where a number belongs, a list where a single value belongs. Here is how to track it down.

ERR:WINDOW RANGE means your graphing window is impossible — Xmin ≥ Xmax or Ymin ≥ Ymax. Fix it in the WINDOW menu or reset instantly with ZOOM 6.

ERR:ARGUMENT means a function received the wrong number of inputs — too few or too many. Here is the correct argument list for the functions that trigger it most.

ERR:UNDEFINED means you referenced a variable, list, or matrix that does not exist in memory — often after a RAM clear. Here is how to restore or re-create it.

Getting a "bad token" or invalid token error when sending files with TI Connect CE? It is usually a corrupt or incompatible file. Here are the 4 fixes that work.

Your TI-84 says sin(30) = -0.988 instead of 0.5? The calculator is in radian mode. Here is how to switch to degrees, when to use each mode, and how to convert without changing the setting.