XLS ERROR from OAK!Merge: Error while connecting to an import source. Unexpected error from external database driver(1).
This Error is a new issue caused by a security update by Microsoft. Microsoft is blocking the use of XLS files. They were last used in 2003. The current format is XLSX files, and they work. We are writing a new OAK!Merge driver for XLS, XLSX, and XLSM which will be released in Jan 2018 for v20 of OAK!Merge. v19 and earlier will no longer support XLS files due to this change by Microsoft.
For v19 and earlier, you can SAVE AS to a CSV or SAVE AS an XLSX file type to use with OAK!Merge. They both work fine.
If you look at your source types in OAK!Merge and you have XLS but do not have XLSX, then you are probably missing the free drivers from Microsoft. OAK!Merge Advanced and Pro, support XLS and XLSX files.
You can add the XLSX by loading the drivers shown below:
Microsoft Access Database Engine 2010 Redistributable
pick 32 bit> AccessDatabaseEngine.exe
Download here: Access, Excel 2007+ www.microsoft.com/en-us/download/details.aspx?id=13255