- What plugin is claimed as missing?
- Is the document created from you?
- Are you sure that this document has not been created in a later version?
- What OS do you use? Is it compatible to CS6?
It could be the way you removed/uninstalled your InDesign wasn't the right way hence some InDesign components were left behind and conflicted with new installation.
I suggest that you uninstall your InDesign once again but this time use Adobe Cleaner Tool which should uproot the software and remove any remnant components.
CAUTION: Read Adobe instructions carefully, make sure you back-up before attempting to use Cleaner Tool, deactivate your Adobe applications in advance, and remember this tool will remove all Adobe applications not just InDesign!
The "missing a plugin" message means it was created in a later version of InDesign, not the very old CS6.
It doesn't tell me what plug in is missing the exact message is "Adobe InDesign may not support the file format, a plug-in that supports the file format may be missing, or the file may be open in another application." The document was created by me and I was using it when InDesign crashed, when I went to open it I got the messsage. I am using OS 10.11.6. I have been using it with my Adobe Creative suite for a couple years.
I got the message before I reinstalled. I had to download the software from the adobe site and reinstall it this morning. I am getting the same message when I try to open my document.
It is the same software that I have had for 3 years.