You can do it by temporarily creating the old directory path (if possible), moving the files there, setting a Linked Attachment Base Directory, moving the files back to where you want them, and then updating the base directory setting.

If you can't or don't want to do that, the Zutilo plugin can batch-edit linked-file paths.

Note that the way to avoid this in the future is to always use a Linked Attachment Base Directory.

it also removes the first letter of the filename

@urbanizationist: This issue with Zutilo has also been reported here: https://forums.zotero.org/discussion/84006/moving-the-linked-files-folders-to-a-different-drive

Do you remember whether you clicked the "replace all instances" check box? Are you using a Windows setup in addition to your MacOS system?

In the linked discussion, you can find a script that might help fixing the filenames.

I'm using Zutilo 3.8.1 installed today. I don't believe I clicked 'replace all instances'. I do have a version on a Windows machine but I haven't run Zotero on it for over a month.

I tried using the javascript that you posted on 25th Dec 2020. It runs but doesn't update the attachment path. Though I wasn't clear if it runs as is, or whether I had to replace the generic names (oldfullpath / newfullpath) in the script with my actual pathnames.

@urbanizationist: I updated the script. The output is more verbose now.

The script currently shows "Values for last broken item", but you should realize that the "new full path" is only saved to the database if it is the proper path of a file. If the new filename seems to be the correct one, your problem is most likely that the directory isn't correct. As I wrote above, the directory needs to be corrected before using the script. Use Zutilo's "Show attachment paths" function to see the directory saved in Zotero's database. Then compare that with the actual file directory. See here:

https://forums.zotero.org/discussion/comment/363117/#Comment_363117

(If the settings for the Linked Attachment Base Directory are confusing to you, reset it to use absolute paths. This shouldn't be necessary, though.)

We should be able to help you if you could post the "Values for last broken item" when running the script with one broken attachment selected. In addition, post the value you get when running "Show attachment paths". Finally, also post the actual file path. That should provide all the necessary information.

@hidetonakamura: You could try replacing the initial path "\directory\. " with "\directory\". But please read through https://forums.zotero.org/discussion/comment/363117/#Comment_363117.

@urbanizationist, @hidetonakamura: Here's a script for checking properties of your linked attachments that are broken. The script won't modify anything. It will only show you some of your attachment settings so you better understand your current situation. (You need Zutilo to run it.)

Select a broken linked attachment, go to "Tools" -> "Developer" -> "Run JavaScript", and paste in and run this code:

// Check properties of linked attachments that are broken
var basePath = Zotero.Prefs.get('baseAttachmentPath');
const mode = Zotero.Attachments.LINK_MODE_LINKED_FILE;
var attArray = ZutiloChrome.zoteroOverlay.getSelectedAttachments(mode);
var attachmentTitle, attachmentPath;
attachmentTitle = attachmentPath = '';
var m = 0;

for (let i = 0; i < attArray.length; i++) {
if (await attArray[i].fileExists()) continue
m++;
attachmentTitle = attArray[i].getField('title');
attachmentPath = attArray[i].attachmentPath;
};

var msgCheck = attachmentPath.startsWith('attachments:');
var msg1 = `attachments: Linked Attachment Base Directory!`;
var msg2 = `The attachment is saved with an absolute path!`;
var messageBaseDir = msgCheck ? msg1 : msg2;
var messageBroken = `\n----\n
Values for the last broken linked attachment:\n\n
Attachment title: \n\n${attachmentTitle}\n\n
Attachment path (saved in Zotero\'s database): \n\n${attachmentPath}\n
-> This path is broken!\n
-> ${messageBaseDir}`;

return `Summary of selected linked attachment items:
${attArray.length} item(s) selected
${m} item(s) broken\n
Linked Attachment Base Directory:
${basePath ? basePath : 'Not defined. Using absolute paths!'}\n
${(m > 0) ? messageBroken : ''}`;

I have run this for one of my collections which has 63 references with attachments. The script found only 21 references and counted 16 of the links broken. I then tried selecting 30 references and it only counted 13 of which 10 were broken. For some reason it doesn't scan all selected references.

Is there a simpler way I can just tell Zotero to look in the new folder for all attachments? Using the Zotilo file path tool risks corrupting all my filenames through the loss of the first letter.