Gimp does not allow me to select any format other than A0 for new image

I know this is old. but for me, not even re-install a newer version solved my problem. I also checked in the templaterc (C:Program FilesGIMP 2etcgimp2.0) file, and it looked normal. delete it and re-installed again but nothing!

The only thing I could really do was manually create the format I needed and save it as a new template. going to File -> save as a new template.

I write this if this helps anyone.

I can't replicate the problem. For me the template dropdown has A4 available. I don't know why you don't have that option available. Perhaps you might want to consider re-installing the lastest version just to make sure, or if you feel so inclined, you can have a look at the templaterc file stored in the program directory. You can add templates in there by editing the file in a text editor.

However it doesn't matter really, since you can just create your own custom size anyway.

To manually create an A4 canvas, type a height of 297mm, and a width of 210mm. Note in the screenshot below there has been some rounding of the sizes due to the fact that one pixel is the smallest unit in a raster image, but it's only a few hundredths of a millimetre and therefore insignificant.

For example