Error in batch process converting raster from .img to .tif in QGIS 3.4.8

I’m a long time GIS user but new to QGIS. I can convert single raster files in .img format to .tif files in QGIS 3.4.8 without any issues. However, I cannot batch process the same files. The Python error message is:

2019-05-29T16:58:13     WARNING    Traceback (most recent call last):
              File "C:/PROGRA~1/QGIS3~1.4/apps/qgis-ltr/./python/pluginsprocessingguiBatchAlgorithmDialog.py", line 88, in runAlgorithm
              parameters[param.name()] = wrapper.parameterValue()
             AttributeError: 'NoneType' object has no attribute 'parameterValue'

The parameters in the batch file window are the same as in the single file processing window. Can anybody point me to a solution?

The log in the processing window is empty. The general messages window contains the message below which only points me to the Python Error tab.

2019-05-30T06:57:52     WARNING    Python error : An error has occurred while executing Python code: See message log (Python Error) for more details. 

When processing a single file (which works fine) the Log window displays this information:

Processing algorithm…
Algorithm 'Translate (convert format)' starting…
Input parameters:
{ 'COPY_SUBDATASETS' : False, 'DATA_TYPE' : 0, 'INPUT' : 'G:/Snow Damage Aerials/LRT Test/orthoc190426a_0493.img', 'NODATA' : None, 'OPTIONS' : '', 'OUTPUT' : 'G:/Snow Damage Aerials/LRT Test/orthoc190426a_0493.tif', 'TARGET_CRS' : None }

GDAL command:
gdal_translate -of GTiff "G:/Snow Damage Aerials/LRT Test/orthoc190426a_0493.img" "G:/Snow Damage Aerials/LRT Test/orthoc190426a_0493.tif"
GDAL command output:
Input file size is 4208, 5931

0...10...20...30...40...50...60...70...80...90...100 - done.

Execution completed in 9.20 seconds
Results:
{'OUTPUT': 'G:/Snow Damage Aerials/LRT Test/orthoc190426a_0493.tif'}

Loading resulting layers
Algorithm 'Translate (convert format)' finished