Time Machine: erroneous "not enough space" error?

[bigwig]

I'm getting a "not enough space" error when trying to back up a 1TB disk to a 1TB disk. Time Machine says it needs 953G to back up the 794G on my disk. 😡 The backup disk is newly formatted with Apple Partition Map. Any idea what's causing this?

 

[Enigmafan420]

I'm getting a "not enough space" error when trying to back up a 1TB disk to a 1TB disk. Time Machine says it needs 953G to back up the 794G on my disk. 😡 The backup disk is newly formatted with Apple Partition Map. Any idea what's causing this?

Never seen this before-what options did you use when partitioning the HD?

It would not surprise me if TM needed a small amount of additional space for the back-up (an amount larger than the final "product". But nearly 200 GB seems sort of excessive to me.

 

[bigwig]

Never seen this before-what options did you use when partitioning the HD?

One partition, Apple Partition Map.