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=== The Differences among Empty, Nothing, vbNull, vbNullChar, vbNullString and the Zero-Length String ===quoted from somewhere: '''""''': A zero-length string (commonly called an "empty string") is technically a zero-length BSTR that actually uses six bytes of memory. In general, you should use the constant vbNullString instead, particularly when calling external DLL procedures.'''Empty''': A variant of VarType 0 (vbEmpty) that has not yet been initialized. Test whether it is "nil" using the IsEmpty function.'''Nothing''': Destroys an object reference using the Set statement. Test whether it is "nil" using the Is operator:If obj Is Nothing Then...'''Null''': A variant of VarType 1 (vbNull) that means "no valid data" and generally indicates a database field with no value. Don't confuse this with a C NULL, which indicates zero. Test whether it is "nil" using the IsNull function.'''vbNullChar''': A character having a value of zero. It is commonly used for adding a C NULL to a string or for filling a fixed-length string with zeroes:Path = String(255, vbNullChar)'''vbNullString''': A string having a value of zero, such as a C NULL, that takes no memory. Use this string for calling external procedures looking for a null pointer to a string. To distinguish between vbNullString and "", use the VBA StrPtr function: StrPtr(vbNullString) is zero, while StrPtr("") is a nonzero memory address. [Note: the StrPtr() function may not be a part of the VBA members shown in the Object Browser so it will not AutoComplete. Enter the following line in the Immediate Window to determine if this function is available: ?StrPtr(vbNullString). This should return 0 immediately.]