At the core of this formula, we build a list of row numbers for a given file. Then we use the MAX function to get the largest row number, which corresponds to the last revision (last occurrence) of that file.
To find...

The #NULL! error is quite rare in Excel, and is usually the result of a typo where a space character is used instead of a comma (,) or colon (:) between two cell references. Technically, the space character is the "...

The SUMPRODUCT function accepts one or more arrays, multiplies the arrays together, and returns the "sum of products" as a final result. If only one array is supplied, SUMPRODUCT simply returns the sum of items in the...

About spilling and the #SPILL! error
With the introduction of Dynamic Arrays in Excel, formulas that return multiple values "spill" these values directly onto the worksheet. The rectangle that encloses the values is...

About the #DIV/0! error
The #DIV/0! error appears when a formula attempts to divide by zero, or a value equivalent to zero. Like other errors, the #DIV/0! is useful, because it tells you there is something missing or...

The #NUM! error occurs in Excel formulas when a calculation can't be performed. For example, if you try to calculate the square root of a negative number, you'll see the #NUM! error. The examples below show formulas...

The #VALUE! error appears when a value is not the expected type. This can occur when cells are left blank, when a function that is expecting a number is given a text value, and when dates are evaluated as text by Excel...

With the introduction of Dynamic Arrays in Excel, formulas there is more emphasis on arrays. The #CALC! error occurs when a formula runs into an calculation error with an array. The #CALC! error is a "new" error in...

In this example, the goal is to count the number of cells in a range that do not contain errors.
Working from the inside out, we first use the ISERROR function on the entire range:
ISERROR(B5:B14) // check all 10...

FIND returns the position (as a number) of the first occurrence of a space character in the text. This position, minus one, is fed into the LEFT function as num_chars.
The LEFT function then extracts characters...

Working from the inside out, the ISERRROR function returns TRUE when a value is a recognized error, and FALSE if not.
When given a range of cells (an array of cells) ISERROR function will return an array of TRUE/FALSE...

The #NAME? error occurs when Excel can't recognize something. Frequently, the #NAME? occurs when a function name is misspelled, but there are other causes, as explained below. Fixing a #NAME? error is usually just a...