I have create or copy 11 .pdf+text files int DEVONthink
7 of them are readable.
4 of them are stored in ~Library/Application Support/Devonthink/Files
I can read the text.
I can open this .pdf.
I can open this .pdf with previev of Mac OS X
I cannot read 4 files.
I cannot open 4 files with previev of Mac OS X
I have copy 2 identical .pdf files on WIN XP.
a) I have send it to my mac via mail and copy it in DT
b) I have store it on a USB stick and copy it in DT
File a) is OK in DT, I can read it in preview and open it with external preview of Mac OS X.
File b) is not OK in DT like a)
I have done following different workflows (assumption)!!!
Make copies from Internet/Print/Save to DT
Make copies from Internet to Desktop
Make copies on XP to USB
Make copies on XP and send it to the Mac via Mail
Make copies on XP and move it direct from the stick to DT
Make copies on XP and move it via desktop to DT
No mystery here. When you imported the PDF file to DEVONthink from the mounted USB stick, you must have had your DT Preferences for PDF & PS set as “Files: Link to Originals.” Therefore, when you unmount the USB stick, DT cannot find the original PDF when you seek to open the file externally – the file is no longer available. (This is the preference setting I use for my own DT database; I keep my PDF files external to the DT database on a mounted volume, and just import the text into DT – or, in DT Pro, use Index import of PDFs.)
There are two other options in DT Preferences for importing PDF files; “Files: Copy files to database folder” or “Files: Copy files into database.” If either of those options had been set when you mounted the USB stick, a copy of the PDF file would have been imported into DT and the PDF file could have been opened externally, whether or not the USB stick remained mounted. (Of the two options, I would recommend the first in this paragraph, copy the PDF files into the database folder. Even if the database becomes corrupted, the files can still be recovered from the database folder. I plan to use this option for an upcoming database project.) Note: I’m not certain whether both options are in DT PE 1.8, but they are available in DT Pro 1.9 alphas and will certainly be available in DT 1.9 PE.