Just learned that foreign source income for funds with less than 50% in foreign investment do NOT qualify for the Form 1116 credit. Therefore, the investment company (in this case, Vanguard, for VT), does not list the foreign source income percentage in their documentation. But TurboTax still insists on having that number for Form 1116.
Since only a few 100$ were involved, rather than trying to figure out how to make TurboTax work around this (there WERE foreign taxes listed on the 1099-DEV, and therefore Turbotax WANTED a foreign source %%), I just switched to Schedule A deduction instead of Form 1116 credit -- the difference was a few dollars, well worth it to avoid struggling with a TurboTax Catch-22 for hours (and waiting for the IRS to issue the final Form 1116).
