Welcome,
Unless your dog has been eating alot of bones, It could be a problem with her liver or gall bladder. Bile often makes the stools appear brown so if there is no bile getting to the stools when they are being processed in the gastrointestinal tract, then the stools appear white. Bile also breaks down fat so it can get absorbed into the body. So if the fat is not getting absorbed, it comes out undigested in the stool and appears white. This is diagnosed with BLOODWORK. There are medications that help with this.
Let us know, Karla
Do you feed the dog bones? I've heard that calcium can cause white stool. If I were you I'd call the vet and ask them. It's better to be safe than sorry.
Is this fresh stool or has it been sitting around for a while? Often old feces will turn white.
Has your dog been eating bones? Sometimes too much calcium can cause this.
If nine of those apply and it continues, best to have a Vet check and take a sample in. This could be caused by gallbladder, pancreas or bile duct problems.