problems with materials when I sync from max, materials can’t be rescaled
and I can’t change the scale either.
Hi there, please check if Individual UV is turned on, it should be the cause of the problem:
Please refer to the instructions for Individual UV in the user manual: When this option is turned down, this texture has a separate UV. You can stretch, offset, and rotate it individually, or you can use Triplanar mapping. This function is suitable for cases where you want to adjust a texture channel individually. For example, when you want to pan the base color map while keeping the normal bump unchanged.
This is because models synced to D5 using the D5 converter do not currently support right-clicking to open the location of the mapping, which is expected to be supported in the next release. 
right, all the materials I import come with Individual UV enabled by default on all maps of all materials,
I will have to go one by one off
I’m sorry for the inconvenience. This is currently the case, when a 3ds Max model has a texture, exporting to d5a turns on Individual UV, this is mainly to ensure that the texture in max has the correct effect in D5. I have fed this back to our product team and we will re-evaluate this.