QBSDK Log File QBSDKLOG.txt

For Windows 7/8/8.1/10 C:\ProgramData\Intuit\QuickBooks and edit the qbsdk.ini file.

For Windows XP and Vista C:\Documents and Settings\All Users\Application Data\Intuit\QuickBooks and edit the qbsdk.ini file.

Add/Edit the following lines:

[Log]
Level=verbose
UnlimitedSize=Y
[Parser]
DumpRequestData=Y

Restart QuickBooks and run the add-on that causes the problems.

When you finish, don't forget to restore the Level in qbsdk.ini to:
Level=info

QB SDK Log Location:
C:\Documents and Settings\All Users\Application Data\Intuit\QuickBooks\qbsdklog.txt
C:\Program Files\Common Files\Intuit\QuickBooks\qbsdklog.txt