I have a logo in my sheet format that appears corrupted every time I open a file again. It does not happen initially with a new drawing though. It happens with both part and assembly drawings, but it is an issue that just started today after weeks of it working fine. I can fix it momentarily by going through properties and reattaching the sheet format, but the next time the file opens, it is corrupted. Here are some pictures of what it should look like and what it looks like when corrupted.