错误原因：
Couldn't save uncommitted changes. Tried to save uncommitted changes in stash before Update, but failed with an error. Couldn't stash file://H:/IdeaProjects/SVSP_0.4: git-write-tree: error building trees Cannot save the current index state
经过逐步排查发现是同事上传了多余的文件造成了集体无法更新，解决方案如下：
进入你的项目目录，我的目录是：H:IdeaProjectsSVSP_0.4,右键选择Git Bash here
输入git status会看到如下信息，注意是Unmerged paths这一段
Unmerged paths: (use "git reset HEAD <file>..." to unstage) (use "git rm <file>..." to mark resolution) both deleted: .idea/artifacts/SVSP0_4.xml
找到原因，是上传了多余的文件，需要删除both deleted: 后面的 .idea/artifacts/SVSP0_4.xml这个文件
输入 git rm .idea/artifacts/SVSP0_4.xml
再次进入IDEA更新即可解决问题
转载：https://blog.csdn.net/lujiachun1/article/details/85248558
错误差不多，用以上方法解决了我的问题，这里做下转载记录