Source Error 3751: barcode contains invalid characters - Issues with the apostrophe symbol in barcodes Symptom You encounter an issue with apostrophes being "invalid characters" for the particular barcode symbology, even though the barcode supports the apostrophe symbol. Environment BarTender Integration Builder Fix/Answer First, make absolutely certain that the barcode symbology does indeed support the apostrophe character. For this example, I will be using the Code 128 symbology. Next, it is important to know that there are two kinds of apostrophes out there: This is the "standard" apostrophe when entered from a US English keyboard: ' This is the other apostrophe that might be used by other region's keyboards: ’ By default, a new Code 128 barcode has the Text Encoding setting (within Symbology and Size) set to "US, Western Europe (7-Bit ASCII)", which does not support the "foreign" apostrophe. The apostrophe will ...