Help with an InDesign file that will not open

[Gypsynaut]

Hello - I created a project in InDesign and after editing for a few days, today it did not allow me to open it. It states: "Cannot open the file "...".  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."  It is not open in another application and I was just editing 15 hours ago.  Not sure what changed overnight, but any suggestions on potential plug-ins or intalling support software??  Thank you!

[Derek Cross]

Which version of InDesign and OS?

Presumably you didn't make a back-up copy of the file?

[Gypsynaut]

Hi Derek - InDesign 2020 (just installed last week).  OS is Catalina v.10.15.3

Only back up is a PDF,  so not helpful for editing.  The ID file was saved only to replace the former file, so no additional copy that I can find.  

[John Mensinger]

Was there a crash while the file was open?

Close InDesign and check the folder where the file is stored for a file with the extension .idlk. If there is one there, delete it, then relaunch InDesign and attempt to open your file.

[Gypsynaut]

I'll try that ... also, no crash. A mystery to me! I'm updating my OS as well so let's see what happens in a few minutes.... fingers crossed!

[Gypsynaut]

Well, I don't know how it opened, but I found the original file (still .indd extension) in documents, and opened it from there. That miraculously did the trick!  Not sure why I could not open from InDesign directly, but just grateful I recovered it!  Thank you all for your responses and ideas!  

[SJRiegel · Accepted solution]

There is a script that will attempt to blind-open the file and export it as idml.  

This is a older script, so I don't know if it works with the newest versions of InDesign, or if an updated version exists.

https://www.hilfdirselbst.ch/foren/gforum.cgi?do=post_editlog;post=475991;