Try either of these.
Possible Solution 1:
Delete ModsConfig.xml from config folder manually. Unzip ModsConfig.xml (From the modpack) to the config folder.
Possible Solution 2:
Unzip the modpack ModsConfig.xml anywhere
Open it in a text editor
Ctrl+A (select all)
Ctrl+C (copies selected stuff)
Open the vanilla (original) ModConfig.xml
Ctrl+A (select all)
Ctrl+V (paste what you copied earlier selected stuff)
Save the file over the original (make sure to save as .xml, )
How to save as a .xml
1) File-> Save as-> Select document you wish to save(Or name)
2) change "Save as type:" to "All Files"
3) save
Possible Solution 1:
Delete ModsConfig.xml from config folder manually. Unzip ModsConfig.xml (From the modpack) to the config folder.
Possible Solution 2:
Unzip the modpack ModsConfig.xml anywhere
Open it in a text editor
Ctrl+A (select all)
Ctrl+C (copies selected stuff)
Open the vanilla (original) ModConfig.xml
Ctrl+A (select all)
Ctrl+V (paste what you copied earlier selected stuff)
Save the file over the original (make sure to save as .xml, )
How to save as a .xml
1) File-> Save as-> Select document you wish to save
2) change "Save as type:" to "All Files"
3) save