Simone
和楼主的问题一样，主要原因是搭激橡我们用的是免费版，有些pro的功能受限。我有个文件也是想添加标签，在警告的时候选择了铅轮yes，结果出现了水印。目前为止无法删除水印。然后我去官网上查了一下，发现果然无法删除，见http://www.tracker-software.com/knowledgebase/186-I-have-a-problem-with-watermarks-being-added-to-my-document-after-opening-it-in-PDF-XChange-Viewer最后一段：There is no way that PDF-XChange Viewer will add water marks unless "Yes" is selected this warning. Once added, these watermarks cannot be removed.If you want to try out a "Pro" feature it would be prudent to save a copy of your original document first because, as noted above, as the addition of the watermarks cannot by reversed by using Edit --> Undo.当然也不排知旁除高手能够解决这个问题。所以楼主一定要先保存好原件，然后慎用pro功能，平时可以隐藏。（里面有个选项 编辑——参数设置——注册，隐藏选项卡打勾就行了）。未发现有好用的注册码，所以我也一直用免费版的，对于日常操作，感觉已经相当不错了。网上好像有pro的破解版，不过不知道干净不。
