Base map generation fails when exporting into an existing folder

[chrisgee]

When base map generation is configured for qfieldsync, exporting (wire) to an empty folder works fine. When the folder was previously populated by an export, base map generation fails.

QFieldSync version 4.13.1
QGis Version 3.40 LTR

[suricactus]

Fixed in opengisch/libqfieldsync#109