Time Machine file illegible

[AndrewRM]

My largest file backed up on the Time Machine is accessible but nearly impossible to read. Shorter files are fully legible (see attachment).

What is the reason?

 

[Cory Cooper]

Hello and welcome.

-Which version of OS X/macOS?
-Can you give a little more explanation for your question, as I am unsure what you are asking?
-Your screenshot attachment isn't legible - can you upload it again?

Thanks,

C

 

[AndrewRM]

That's right. It is illegible. That's how it appears for one major file, the one of importance. Other files are as you would expect. I am using Mac OS 10.15.5.

 

[Cory Cooper]

OK, thanks.

I think I understand now - the screenshot is of the file in question after it is opened. I was thinking it may be a Finder windows listing of the files. It looks like this may be a JPG/PNG image file, correct? If not, what type of file is it?

If it is an image file, then it looks like it may be a thumbnail or preview of the original file, not the full resolution image.

C

 

[Lufbrarunner]

Did you open this by clicking it in Time Machine or had the file been restored back to it' original position?
If its the former it could be as Cory says, a low resolution image.

 

[AndrewRM]

OK, thanks.

I think I understand now - the screenshot is of the file in question after it is opened. I was thinking it may be a Finder windows listing of the files. It looks like this may be a JPG/PNG image file, correct? If not, what type of file is it?

If it is an image file, then it looks like it may be a thumbnail or preview of the original file, not the full resolution image.

C

No, it's not a JPG or PDF image file. It's a Numbers file - similar to Excel. Have the recent changes in Catalina caused this?

 

[AndrewRM]

Anyone else with ideas on this? Thanks

 

[oldscribe]

Hi,

It's a Numbers file - similar to Excel.

Two questions,
1) Are you constantly updating this file IE changing it?
2) Can you still open the original fine?

Also remember that Time Machine only copies a file when it changes, but it just creates snapshots for each backup that use what are known as hard links for every other file on your backed-up drive. Thus my questions.

 

[AndrewRM]

Additional datapoint are added about once a week. The file has gradually grown over the years. I have never seen this problem before. Fortunately I can still open the originating file.

Since you seem to understand the backup scheme (as I do as well) let me tell you that one other thing happened at the same time. One of the columns in Time Machine file has become blank. In the originating file (which is then backed up multiple times per day on the Time Machine) that column is not blank. When I saw this occur I went to the TM to make the correction and found it was not possible because I could not see clearly what was there.

Thanks

 

[oldscribe]

Hi,

I am using Mac OS 10.15.5.

Did you ever notice this with 10.15.3 <> 10.15.4 or is it a recent thing?

 

[AndrewRM]

I never saw it until early June and don't know if if it occurred much sooner than that as I do not check my backups frequently and rarely need them. All I can say definitively is that through the murk the missing column did not appear until June 7. That is, on June 6 the column was not blank although I cannot read the contents of it. Whether or not the missing column is associated with the murky output is uncertain although it is suggestive.