Hi,The problem I describe below is not new (I observed this at least since version 3) but this time I took the time to investigate more deeply...From time to time, LR tells me that the XMP file of a given image is no longer in sync with the metadata in the catalog. Most often, this is correct because I made changes without recording the XMP file (Ctrl-S - I'm not using the automatic XMP updating mode). But many times, this information is simply wrong. I didn't change anything to the image and suddenly, the little down arrow appears in the upper left corner of the thumbnail.Hitting Ctrl-S may or may not fix the problem. Sometimes, the little down arrow reappears after a few seconds or minutes although I didn't do anything (hands away from keyboard and mouse).I recently did the following test for multiple images unduly displaying the "metadata status changed" flag. I compared the following values : 1. Windows "last modified" timestamp for the XMP file.2. Value of the xmp:MetadataDate field in the XMP file.3. touchTime column value for that image in the Adobe_images table of the catalog (which is a SQLite database).The touchTime value is stored in a special format, so I had a hard time converting it to a readable date/time value. However, I will not explain this and how I navigated the database in order to access this timestamp (this requires some knowledge about databases). Result:For all the images tested, values #1 and #2 were always strictly identical. The touchTime value was always off (sometimes about 10-15seconds, sometimes much more). So no wonder that LR thought that the XMP file and the metadata in the catalog were not in sync.Moreover, the difference in time can be negative of positive. So LR displays the up or down arrow accordingly (meaning that the XMP file is older or newer than the metadata in the catalog, respectively - which is wrong in both cases).I explained above that sometimes, the image reappears as "not in sync" just a few seconds or minutes after I did a Ctrl-S. In that case, a quick look at the database showed me that the touchTime field had not been updated. So the time difference causing the image to be flagged as "not in sync" was still there. In that case, the problem can be fixed by reading the metadata from the XMP file which was actually correctly updated. This operation updates the catalog and everything is in sync again.Anyway, there's something very wrong in the computation of the touchTime value of the Adobe_images table. That seems to be obvious. This wrong timestamp generates in turn a wrong metadata status.I made another interesting test :1. I started from a situation were 0 image was flagged as "not in sync" with the XMP file.2. I purged all 1:1 previews and started a Build all 1:1 previews.3. In Library mode, i setup a filter to show only the images that had the Metadata Status set to "has been changed". I got a cup of coffee and waited.At the beginning of teh generation process, no image was displayed in the grid, as expected. While LR was building the previews, images unduly tagged as "not in sync" started to appear. I got about 200 of them. For all these images, the metadata status was just plain wrong. These were finalized images not modified since a long time and for which the XMP file had been timely updated after the last modification. I checked the touchTime field for some of them and each time it was different from the Windows "last modified" timestamp and from the xmp:MetadataDate field of the XMP file as mentioned above. So now I know what's going wrong but I'd like to have this problem fixed after all these years.Thanks in advance.