In general it is recommended to use the specially created import filters marked with "label". These will copy the pmid into the field label, which allows you to deduplicate on PMID via the field label.
I have developed a series of videos on the deduplication method that are available through Youtube:
Phase 1: Change Settings
Phase 2: Normalize Imported References
Phase 3: Selecting and Removing Duplicates
Steps in the deduplication process:
|Set Field Preferences (step 1)||Steps to remove duplicates (step 6)|
|a||Label||In step 5 (see above), first click Skip, then click Cancel. Next press [Delete] to remove all selected duplicates without manual assessment|
|b||Author | Year | Title | Secondary Title (Journal)||Press [Delete] to remove all selected duplicates without manual assessment|
|c||Author | Year | Title | Pages|
|d||Title | Volume | Pages|
|e||Author Volume Pages|
|f||Title||Compare page numbers of consecutive references. If page numbers are present and different, examine journal titles and authors. Deselect false duplicates with [Ctrl-Click]. Blank pages or pages starting with the number 1 are usually true duplicates, but check journal titles and author names when in doubt, especially when multiple consecutive blank pages are selected. After checking the entire list, remove the remaining selected duplicate references with [Delete].|
|g||Author | Year||If a true duplicate is found, deselect all references by clicking the first true duplicate reference without holding [Ctrl]. Compare subsequent references on page numbers: if two adjacent references have the same page numbers, select the one with the largest record number with [Ctrl-Click]. After checking the complete list, remove the remaining selected references with [Delete].|
To ease the deduplication process in EndNote it is recommended that instead of using the traditional export and import workflows you use the following steps.