It seems Renoise on High Sierra cannot read or set manufacturer’s info inside an au-preset.
Saved with 10.13.4(.aupreset, ambience au):
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>data</key>
<data>
AAAAAAAAAAAAAAAVAAAAAD9CMjkAAAABPqmJ+QAAAAI+64UfAAAAAz8AAAAAAAAEPwo9
cQAAAAU/AAAAAAAABj8KPXEAAAAHPr1wpAAAAAhCcAABAAAACULIAAAAAAAKAAAAAAAA
AAs9zMzNAAAADAAAAAAAAAANP164UgAAAA7A7My8AAAAD0qXt6MAAAAQAAAAAAAAABEA
AAAAAAAAEkEgAAAAAAATQ/r/7wAAABRCyAAA
</data>
<key>manufacturer</key>
<integer>0</integer>
<key>name</key>
<string>Sascha Kujawa _ Room</string>
<key>subtype</key>
<integer>0</integer>
<key>type</key>
<integer>0</integer>
<key>version</key>
<integer>0</integer>
</dict>
</plist>
Saved in 10.12.6 (.aupreset, ambience au):
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>data</key>
<data>
AAAAAAAAAAAAAAAVAAAAAD8ZmZ4AAAABQAAAAAAAAAI9dcKOAAAAAz8R64UAAAAEProt
cwAAAAU/AAAAAAAABj9R64QAAAAHAAAAAAAAAAhCyAAAAAAACUIEAAgAAAAKPUzMzAAA
AAs+YPnTAAAADMDHrhEAAAANPw9cKQAAAA7A7hRuAAAAD0qxpccAAAAQAAAAAAAAABE+
zMzWAAAAEkEgAAAAAAATQlrMzQAAABQAAAAA
</data>
<key>manufacturer</key>
<integer>1298229066</integer>
<key>name</key>
<string>drums ambience hi2</string>
<key>subtype</key>
<integer>130071762</integer>
<key>type</key>
<integer>1635083896</integer>
<key>version</key>
<integer>0</integer>
</dict>
</plist>
If you now set the integer of manufacturer, type and subtype to 0, Renoise will again read the .aupreset. But I don’t know what then will happen on song save/next song load. Also seems to be a way to completely mess up data…